Showing papers on "Amylase published in 1983"
TL;DR: The gene coding for amylase has been isolated and sequenced from Bacillus subtilis by cloning in lambda Charon4A and pBR322 and shows a large open reading frame with a translated molecular weight of 72,800 and a presumed signal sequence of approximately thirty-two amino acids.
Abstract: The gene coding for amylase (EC.3.2.1.1) has been isolated and sequenced from Bacillus subtilis by cloning in lambda Charon4A and pBR322. The entire coding sequence and large preceding and following regions, comprising the presumed transcriptional and translational regulatory regions, were sequenced. The coding sequence shows a large open reading frame with a translated molecular weight of 72,800 and a presumed signal sequence of approximately thirty-two amino acids. When the intact gene is present in Escherichia coli, it confers the ability to degrade starch, indicating that the gene is expressed in a functional state.
198 citations
TL;DR: In this paper, pigs were fitted with a re-entrant cannula, which was formed on either side of a short pouch of duodenum into which the pancreatic duct opened.
Abstract: 1. Six pigs, initially of 35 kg mean live weight, were each fitted with a re-entrant cannula. This was formed on either side of a short pouch of duodenum into which the pancreatic duct opened and which contained a simple cannula linked to the centre of the re-entrant cannula.2. Each pig received two diets: diet A was based on wheat starch, sucrose and casein, while diet B was based on barley and soya-bean meal. The diets were given in equal amounts at 12 h intervals.3. Digesta and pancreatic juice were collected continuously during three 12 h periods for each pig on each diet.4. Mean duodenal output: dietary intake values for diets A and B respectively were: digesta 1·80, 2·86; dry matter 1·05, 1·03; nitrogen 1·05, 1·06; trichloroacetic acid (TCA)-soluble N 7·69, 9·10; glucose 0·97, 0·89. For diet A the proportion of TCA-soluble N in total N rose from 13 to 50% during 12 h, while it was approximately 50% throughout 12 h for diet B.5. Mean total pepsin (EC 3.4.23.1) activities (units/24 h) were 760449 (diet A) and 1466571 (diet B).6. Salivary and gastric secretions were calculated to be approximately 4 and 8 kg/24 h for diets A and B respectively.7. Mean flows in pancreatic juice (g/24 h) for diets A and B respectively were: juice 1204, 2182; protein 10·94, 12·10; N 1·98, 2·14; ash 9·46, 17·31; sodium 3·88, 6·91; potassium 0·23, 0·54: calcium 0·031, 0·046; phosphorus 0·024, 0·026.8. Mean total enzyme activities (units × 10−3/24 h) for diets A and B respectively were: trypsin (EC 3.4.21.4) 138, 114; chymotrypsin (EC 3.4.21.1) 84, 84; carboxypeptidase A (EC 3.4.2.1) 5, 4; carboxypeptidase B (EC 3.4.2.2) 15, 17; amylase (EC 3.2.1.1) 1061, 981.9. It was calculated that the minimum amount of endogenous N from saliva and gastric secretion was 0·3–0·6 g in 24 h. This assumes no absorption of N occurred anterior to the duodenal cannula.
172 citations
TL;DR: The reason for the different digestibilities of carbohydrates was investigated and discussed in this paper, where the inclusion of soluble starch products in the diet increases the volume of intestinal juices and accelerates the passage through the intestine, thus reducing the time available for absorption.
166 citations
TL;DR: Barley (Hordeum distichum cv Klages) kernels were shown to contain a factor that converted malted barley α-amylase II to the α-AMylase III form.
Abstract: Barley (Hordeum distichum cv Klages) kernels were shown to contain a factor that converted malted barley α-amylase II to the α-amylase III form. After purification by ammonium sulfate fractionation, ion exchange chromatography on DEAE-Sephacel, and gel-filtration on Bio Gel P60, the factor gave a single band of protein on isoelectric focusing. The purified factor inhibited hydrolysis of soluble starch by α-amylase II from malted barley and germinated wheat (Triticum aestivum cv Neepawa). However, α-amylase I from these cereals was not affected. The inhibitor was not dialyzable and was retained by a PM 10 ultrafiltration membrane suggesting a molecular weight greater than 10,000 daltons. Heat treatment of the inhibitor at 70°C for 15 minutes at pH 5.5 and 8.0 resulted in considerable loss of inhibitory activity.
110 citations
TL;DR: In this paper, the alpha-amylase activity in crude plant extracts is measured using starch azure and two procedures were developed to eliminate the interference of the betaamylases, namely, the dilution procedure and the saturation procedure.
Abstract: The specific measurement of alpha-amylase activity in crude plant extracts is difficult because of the presence of beta-amylases which directly interfere with most assay methods. Methods compared in this study include heat treatment at 70 degrees C for 20 min, HgCl(2) treatment, and the use of the alpha-amylase specific substrate starch azure. In comparing alfalfa (Medicago sativa L.), soybeans (Glycine max [L.] Merr.), and malted barley (Hordeum vulgare L.), the starch azure assay was the only satisfactory method for all tissues. While beta-amylase can liberate no color alone, over 10 International units per milliliter beta-amylase activity has a stimulatory effect on the rate of color release. This stimulation becomes constant (about 4-fold) at beta-amylase activities over 1,000 International units per milliliter. Two starch azure procedures were developed to eliminate beta-amylase interference: (a) the dilution procedure, the serial dilution of samples until beta-amylase levels are below levels that interfere; (b) the beta-amylase saturation procedure, addition of exogenous beta-amylase to increase endogenous beta-amylase activity to saturating levels. Both procedures yield linear calibrations up to 0.3 International units per milliliter. These two procedures produced statistically identical results with most tissues, but not for all tissues. Differences between the two methods with some plant tissues was attributed to inaccuracy with the dilution procedure in tissues high in beta-amylase activity or inhibitory effects of the commercial beta-amylase. The beta-amylase saturation procedure was found to be preferable with most species. The heat treatment was satisfactory only for malted barley, as alpha-amylases in alfalfa and soybeans are heat labile. Whereas HgCl(2) proved to be a potent inhibitor of beta-amylase activity at concentrations of 10 to 100 micromolar, these concentrations also partially inhibited alpha-amylase in barley malt. The reported alpha-amylase activities in crude enzyme extracts from a number of plant species are apparently the first specific measurements reported for any plant tissues other than germinating cereals.
101 citations
TL;DR: The nature of the α-Amy-B2b phenotype and the rare non-parental isozyme patterns found among the recombinant lines indicates that the locus is large and compound, probably involving some degree of intra-locus gene duplication.
Abstract: An analysis of the α-amylase isozymes in GA-treated endosperm of wheat nullisomic-tetrasomics shows that there is more variation at the α-Amy-1 and α-Amy-2 homoeoallelic loci than was previously thought Among the 16 isozymes produced by genes on the group 7 chromosomes, most could be definitely established as products of a single homoeoallele
100 citations
TL;DR: The alpha-amylase produced by Bacillus licheniformis CUMC305 was purified with a 42% yield through a series of four steps as discussed by the authors, and the enzyme showed maximal activity at 90 degrees C and pH 9.0, and 91% of this activity remained at 100 degrees C. The activation energy for this enzyme was calculated as 5.1 x 10 J/mol.
Abstract: alpha-Amylase produced by Bacillus licheniformis CUMC305 was purified 212-fold with a 42% yield through a series of four steps. The purified enzyme was homogeneous as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and discontinuous gel electrophoresis. The purified enzyme showed maximal activity at 90 degrees C and pH 9.0, and 91% of this activity remained at 100 degrees C. The enzyme retained 91, 79, and 71% maximal activity after 3 h of treatment at 60 degrees C, 3 h at 70 degrees C, and 90 min at 80 degrees C, respectively, in the absence of substrate. On the contrary, in the presence of substrate (soluble starch), the alpha-amylase enzyme was fully stable after a 4-h incubation at 100 degrees C. The enzyme showed 100% stability in the pH range 7 to 9; 95% stability at pH 10; and 84, 74, 68, and 50% stability at pH values of 6, 5, 4, and 3, respectively, after 18 h of treatment. The activation energy for this enzyme was calculated as 5.1 x 10 J/mol. The molecular weight was estimated to be 28,000 by sodium dodecyl sulfate-gel electrophoresis. The relative rates of hydrolysis of soluble starch, amylose, amylopectin, and glycogen were 1.27, 1.8, 1.94, and 2.28 mg/ml, respectively. V(max) values for hydrolysis of these substrates were calculated as 0.738, 1.08, 0.8, and 0.5 mg of maltose/ml per min, respectively. Of the cations, Na, Ca, and Mg, showed stimulatory effect, whereas Hg, Cu, Ni, Zn, Ag, Fe, Co, Cd, Al, and Mn were inhibitory. Of the anions, azide, F, SO(3), SO(4), S(2)O(3), MoO(4), and Wo(4) showed an excitant effect. p-Chloromercuribenzoic acid and sodium iodoacetate were inhibitory, whereas cysteine, reduced glutathione, thiourea, beta-mercaptoethanol, and sodium glycerophosphate afforded protection to enzyme activity. alpha-Amylase was fairly resistant to EDTA treatment at 30 degrees C, but heating at 90 degrees C in presence of EDTA resulted in the complete loss of enzyme activity, which could be recovered partially by the addition of Cu and Fe but not by the addition of Ca or any other divalent ions.
99 citations
TL;DR: Properties of amylases in homogenates of midguts of larvae of the granary weevil and maize weevil, Sitophilus zeamais Motchulsky, were studied and two strongly anionic amylase isozymes were demonstrated.
98 citations
TL;DR: Chromatograms of intestinal aspirates suggested that (1->4, but not 1->6) linked oligosaccharides liberated during luminal and brush-border hydrolysis of dietary starch conferred a kinetic advantage on glucose absorption.
Abstract: The intestinal absorption and mucosal hydrolysis of a partial and a complete alpha-amylase hydrolysate of corn starch, simulating the normal intermediary and end products of luminal starch digestion, was studied using an in vivo steady state jejunal perfusion technique in normal human subjects. Alpha-amylase was excluded from the test segment by proximal balloon occlusion. Products of hydrolysis during intestinal perfusion were identified using gel permeation chromatography. Three isocaloric, isotonic sugar saline solutions containing 140 mM glucose, 70 mM maltose and the partial amylase hydrolysate of starch (51.5 +/- 1.4% of glucose content comprising glucose polymers of more than 10 glucose units) were perfused in the first study. Net glucose absorption during perfusion of the partial hydrolysate and free glucose was similar, but significantly faster from maltose (p less than 0.05). Hydrolysis of the polymer fraction containing more than 10 glucose units was significantly slower (29.5 +/- 2.0% of infused load) than the lower molecular weight fraction (56.4 +/- 3.8%, p less than 0.001). As net glucose absorption from the partial hydrolysate was similar to that from glucose, despite the slow hydrolysis of the higher molecular weight fraction, it seemed likely that oligosaccharides in the more rapidly hydrolysed lower molecular weight fractions were exerting a kinetic advantage on glucose absorption. This was confirmed in a second study, where glucose absorption from a complete amylase hydrolysate consisting predominantly of maltose, maltotriose and alpha-limit dextrins, occurred significantly faster (81.8 +/- 4.8 mmol/h/25 cm) than from isocaloric free glucose (55.8 +/- 4.9 mmol/h/25 cm, p less than 0.001). Chromatograms of intestinal aspirates suggested that (1->4), but not 1->6) linked oligosaccharides liberated during luminal and brush-border hydrolysis of dietary starch conferred a kinetic advantage on glucose absorption.
78 citations
TL;DR: An inhibitor of malted barley (Hordeum vulgare cv Conquest) α-amylase II was purified 125-fold from a crude extract of barley kernels by (NH4)2SO4 fractionation, ion exchange chromatography on DEAE-Sephacel, and gel filtration on Bio-Gel P 60.
Abstract: An inhibitor of malted barley (Hordeum vulgare cv Conquest) α-amylase II was purified 125-fold from a crude extract of barley kernels by (NH4)2SO4 fractionation, ion exchange chromatography on DEAE-Sephacel, and gel filtration on Bio-Gel P 60. The inhibitor was a protein with an approximate molecular weight of 20,000 daltons and an isoelectric point of 7.3. The protein was homogeneous, as assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Amino acid analysis indicated the presence of about 9 half-cystine residues per mole. The neutral isoelectric point of the inhibitor suggested that some of the apparently acidic residues (glutamic and aspartic) existed in the amide form. The first twenty N-terminal amino acids were sequenced. Some homology appeared to exist between the α-amylase II inhibitor and trypsin inhibitor from barley. Complex formation between α-amylase II and the inhibitor was detected by the appearance of a new molecular weight species after gel filtration on Bio-Gel P 100. Enzyme and inhibitor had to be preincubated for 5 min, prior to assaying for enzyme activity before maximum inhibition was attained. Inhibition increased at higher pH values. At pH 5.5, an approximately 1100 molar excess of inhibitor over α-amylase II produced 40% inhibition, whereas, at pH 8.0, a 1:1 molar ratio of inhibitor to enzyme produced the same degree of inhibition.
77 citations
TL;DR: Three amylolytic Lactobacillus strains isolated from the chicken crop belonged to the subgenus Thermobacterium and had the lowest amylase activity which was increased only in presence of maltose.
Abstract: Three amylolytic Lactobacillus strains designated LEM 220, LEM 207 and LEM 202 were isolated from the chicken crop. They belonged to the subgenus Thermobacterium. Strain LEM 220 resembled Lact. acidophilus. Amylase production was more abundant in cells grown in media containing amylopectin or starch than in media containing glucose or maltose. Optimum pH and temperature of the amylase were 5.5 and 55 degrees C respectively. Hydrolysis of amylopectin gave maltose, maltotriose and small amounts of glucose. Stain LEM 207 also resembled Lact. acidophilus, but differed from strain 220. It had a lower amylase activity. Optimum pH and temperature of the amylase were 6.4 and 40 degrees C, respectively, and hydrolysis of amylopectin gave maltose, maltotriose and carbohydrates higher than maltopentaose. Strain LEM 202 was similar to Lact. vitelinus. It had the lowest amylase activity which was increased only in presence of maltose. Amylase properties were similar to those of LEM 220.
TL;DR: It is concluded that substance P or a closely related peptide is a functional neurotransmitter in the rat parotid gland.
Abstract: The technique of electrical field stimulation was employed to stimulate the intrinsic nerves of isolated rat parotid gland fragments. Responses to field stimulation were recorded as changes in enzyme secretion (amylase release), radiolabelled ion fluxes (86Rb efflux) and electrophysiological effects (changes in acinar cell membrane potential and input resistance). All effects of field stimulation were abolished by the neurotoxin, tetrodotoxin (TTX). Selective use of pharmacological antagonists revealed that both the sympathetic and parasympathetic nerves to this tissue were being excited by field stimulation. Importantly a significant component of the response to field stimulation persisted in the presence of combined autonomic receptor blockade by atropine, phentolamine and propranolol, i.e. due to release of a non-cholinergic, non-adrenergic neurotransmitter. The non-cholinergic, non-adrenergic neurotransmitter evoked amylase release, 86Rb efflux and electrophysiological effects seen as changes in acinar cell membrane potential and conductance, i.e. stimulus-permeability coupled. Two biologically active peptides, substance P (SP) and vasoactive intestinal polypeptide (VIP) were shown to evoke amylase release in the presence of combined autonomic blockade. VIP however did not evoke any increase in 86Rb efflux, i.e. not stimulus-permeability coupled. All the effects of the non-cholinergic, non-adrenergic transmitter were mimicked by substance P which evokes 86Rb efflux and electrophysiological effects in addition to amylase release. The non-cholinergic, non-adrenergic field stimulus effects on amylase release and 86Rb efflux were abolished or markedly attenuated in tissues which had been desensitized by prior exposure to exogenous substance P. In the presence of VIP, however, the non-cholinergic, non-adrenergic effects persisted and were apparently potentiated. Acute application of the neurotoxin capsaicin first stimulated a transient release of amylase and subsequently abolished the non-cholinergic, non-adrenergic field stimulus-evoked enzyme release. The putative substance P antagonist, D-Pro2, D-Trp7,9 substance P, reversibly blocked the response to both non-cholinergic, non-adrenergic nerve stimulation and exogenous substance P. It was demonstrated however that prolonged exposure to this antagonist is associated with non-reversible and, importantly, non-specific neurotoxic effects. It is concluded that substance P or a closely related peptide is a functional neurotransmitter in the rat parotid gland.
TL;DR: In this article, a simple method of dehulling and demucilaging of linseed was developed, and the solubility of the proteins of the linseed meal in water, 0.5 and 1.0 M NaC1 and 2% sodium hexametaphosphate solutions was determined in the pH range 2-12.
Abstract: A simple method of dehulling and demucilaging of linseed was developed. Solubility of the proteins
of the linseed meal in water, 0.5 and 1.0 M NaC1, and 2% sodium hexametaphosphate solutions was
determined in the pH range 2-12. The solubility was minimum around pH 3-6 and maximum around
pH 8.0. The solubility minimum shifted to pH 0.5-4.5 in 1 M NaCl and to 0.6-5.3 in 2% sodium
hexametaphosphate. The total proteins were characterized by techniques of gel filtration, ion-exchange
chromatography, electrophoresis, and ultracentrifugation. The presence of at least three components
was observed. The meal extracts showed proteolytic and trypsin inhibitor activities but no hemagglutinating
activity. Amylase and amylase inhibitor activities were not detected.
TL;DR: Trestatin complex which exhibited a potent inhibitory activity on various alpha-amylases has been isolated from the culture filtrate of Streptomyces dimorphogenes nov. sp.
Abstract: Trestatin complex which exhibited a potent inhibitory activity on various alpha-amylases has been isolated from the culture filtrate of Streptomyces dimorphogenes nov. sp. NR-320-OM7HB. Three major components, trestatins A, B and C, have been purified by adsorption and ion-exchange chromatography. Their spectral and chemical properties suggested that trestatins were novel basic oligosaccharide homologues each characterized by the possession of a trehalose moiety at the non-reducing end of the molecule.
TL;DR: IgA, IgG, albumin, lysozyme, alpha-amylase and glucosyltransferase were identified in the saliva coat and it is suggested that these proteins may be involved in binding microorganisms to saliva coated hydroxyapatite in model studies.
Abstract: IgA, IgG, albumin, lysozyme, alpha-amylase and glucosyltransferase were identified in the saliva coat which forms on hydroxyapatite exposed to whole saliva. It is suggested that these proteins may be involved in binding microorganisms to saliva coated hydroxyapatite in model studies.
TL;DR: The results support the hypothesis that digestion starts in the endoperitrophic space under the action of amylase and trypsin and is largely completed in the ectoper itrophic space through the catalytic action of several oligomer and dimer hydrolases.
TL;DR: It is proposed that transitory starch degradation in vivo is initiated by hydrolysis; phosphorolysis is most likely restricted to a pool of soluble glucan intermediates.
Abstract: The initial reactions of transitory starch degradation in Spinacia oleracea L. were investigated using an in-vitro system composed of native chloroplast starch granules, purified chloroplast and non-chloroplast forms of phosphorylase (EC 2.4.1.1) from spinach leaves, and α-amylase (EC 3.2.1.1) isolated from Bacillus subtilis. Starch degradation was followed by measuring the release of soluble glucans, by determining phosphorylase activity, and by an electron-microscopic evaluation following deep-etching of the starch granules. Starch granules were readily degraded by α-amylase but were not a substrate for the chloroplast phosphorylase. Phosphorolysis and glucan synthesis by this enzyme form were strictly dependent upon a preceding amylolytic attack on the starch granules. In contrast, the non-chloroplast phosphorylase was capable of using starch-granule preparations as substrate. Hydrolytic degradation of the starch granules was initiated at the entire particle surface, independently of its size. As a result of amylolysis, soluble glucans were released with a low degree of polymerization. When assayed with these glucans as substrate, the chloroplast phosphorylase form exhibited a higher apparent affinity and a higher reaction velocity compared with the non-chloroplast phosphorylase form. It is proposed that transitory starch degradation in vivo is initiated by hydrolysis; phosphorolysis is most likely restricted to a pool of soluble glucan intermediates.
TL;DR: A cDNA segment complementary to the mouse salivary amylase messenger RNA has been inserted into the yeast expression vector pMA 56 behind the promoter of the gene encoding the alcohol dehydrogenase I of yeast.
Abstract: A cDNA segment complementary to the mouse salivary amylase messenger RNA has been inserted into the yeast expression vector pMA 56 behind the promoter of the gene encoding the alcohol dehydrogenase I of yeast. Yeast transformants containing plasmids with the normal orientation of the promoter and the mouse α-amylase cDNA gene produce amylase and release the enzyme in free form into the medium. In one litre cultures with a final cell density of 2·107 cells ml−1 75 μ of amylase is found corresponding to 0.1% of the cell protein. It has been estimated that almost 90% of the amylase synthesized by the cells is excreted. A handy plate assay for colonies excreting α-amylase is described.
TL;DR: It is concluded that short-chain fatty acids act directly on pancreatic acinar cells to stimulate secretion in anesthetized sheep.
Abstract: The secretory response of the exocrine pancreas to short-chain fatty acids has been studied in anesthetized sheep and in isolated lobules. Butyrate, propionate, and acetate stimulated pancreatic juice flow and protein and amylase output in the anesthetized sheep. The secretory response to butyrate was significantly greater than that of propionate or acetate. Rapid intravenous injection of butyrate (625 mumol/kg) caused a 13-fold rise in the juice flow, 26-fold in protein output, and 37-fold in amylase output above the basal levels within 5 min and declined to basal levels over a period of 30 min. Responses to butyrate (625 mumol/kg) were comparable with those obtained with 2 U/kg pancreozymin (Boots). Detectable responses were obtained with 15 mu/kg butyrate, 125 mumol/kg propionate, and 312.5 mumol/kg acetate. The secretory response to butyrate (625 mumol/kg) was not affected by pretreatment with atropine and hexamethonium. In the isolated lobule preparation, amylase release increased in response to butyrate in a concentration-dependent manner, reaching a maximal level at 1 mM and declining at 100 mM. It is concluded that short-chain fatty acids act directly on pancreatic acinar cells to stimulate secretion. The physiological implications of these findings are considered.
TL;DR: An extracellular glucoamylase [exo-1,4-α- d -glucosidase, 1,4α-d -glucohydrolase, EC 3.3] of Endomycopsis fibuligera has been purified and some of its properties studied as mentioned in this paper.
TL;DR: This study supports the possibility that ingested mammary amylase could retain a significant proportion of its original activity after exposure to acid and pepsin in the stomach of young infants.
Abstract: Summary: Mammary amylase is a possible alternate pathway of digestion of glucose polymers and starches, that is most important in early infancy when pancreatic amylase is low or absent in duodenal fluid and responds poorly to stimuli. Human breast milk contains 1000–5000 units of amylase/liter. In order to evaluate the likelihood that a significant proportion of mammary amylase activity would withstand passage through the stomach, purified and unpurified mammary anylase were exposed to acid and pepsin in vitro to simulate the gastric environment found in young infants. Both purified and unpurified enzymes were stable at pH 7.5 with little or no activity lost after 4 h, and approximately 80% retained at 6 h. When incubated at pH 3.5, one-third of unpurified enzyme activity was retained for 6 h; in contrast, the purified enzyme was acid labile losing 80% by 2 h. Addition of bovine serum albumin or breast milk proteins to purified enzyme protected the activity. When unpurified enzyme was exposed to a stepwise decline in pH from 6.5 to 3.5 over 4 h, 50% of the original activity was retained. Unless the concentration was >3750 units/ml, the addition of varying concentrations of pepsin to defatted breast milk incubated at pH 3.5 did not affect any greater decay of enzyme activity despite evidence of peptic digestion of proteins in the reaction mixture. This study supports the possibility that ingested mammary amylase could retain a significant proportion of its original activity after exposure to acid and pepsin in the stomach of young infants. Speculation: Mammary amylase may be an enzyme important to carbohydrate digestion in infancy. The amount that would survive passage through the stomach of a young infant is most probably greater than would be contained in the pancreatic secretions of infants less than approximately 4-6 months of age. The physiologic importance of mammary amylase may be analogous to that of the bile salt stimulated lipase found in human milk.
TL;DR: The fruit weight of cv Dashehari mangoes increased until 91 days after fruit set, together with gradual increases in fructose and reducing sugars as discussed by the authors, and a decline in both starch content and amylase activity was recorded after 91 days growth.
Abstract: SummaryThe fruit weight of cv Dashehari mangoes increased until 91 days after fruit set, together with gradual increases in fructose and reducing sugars. Glucose, fructose and sucrose were identified in the dried mango pulp, glucose and fructose being more plentiful until maturity, whereas later (96–105 days) sucrose was predominant. There was an increase in the total sugar content after 72 days from fruit set. Starch accumulation was slow at first but later increased with a concomitant acceleration of amylase activity. A decline in both starch content and amylase activity was recorded after 91 days growth. The protein content decreased until 44 days after fruit set and then increased during 96 days of further development.
TL;DR: An extracellular amylase produced by Bacillus circulans F-2 was purified to show a single band on SDS polyacrylamide gel electrophoresis.
Abstract: An extracellular amylase produced by Bacillus circulans F-2 was purified to show a single band on SDS polyacrylamide gel electrophoresis. The purified enzyme has a molecular weight of 93, 000, an optimum pH of 6.0-6.5 and an optimum temperature of 60°C. On isoelectric focusing, the enzyme exhibited 2 bands with isoelectric points of 4.88 and 4.93. When acting on amylaceous polysaccharides, the enzyme removed maltohexaose from their non-reducing ends but the produced maltohexaose was then split into maltotetraose and maltose. Although it digested corn starch granules at approximately the same rate as porcine pancreatic and Streptococcus bovis amylases, it digested potato starch granules far faster than those amylases.
TL;DR: Variations in O:N and O:P ratios were related to differences in the nutritional strategy of the different species, based on literature data concerning the anatomy of their mouth parts and their selectivity for animal material in mixed-food experiments.
Abstract: The relationship between respiration, nitrogen and phosphorus excretion and specific activity of amylase and trypsin was investigated from shipboard experiments with several species of copepods from the equatorial divergence area of the Indian Ocean, in June 1978. Statistical analysis of O:N ratios in 6 of the most common species revealed three main groups: a group displaying low O:N (Pontella fera, Candacia pachydactyla); a group with high O:N (Undinula darwini, Euchaeta marina, Temora discaudata); and a species displaying an intermediate O:N ratio: Scolecithrix bradyi. O:P and N:P did not differ significantly between species. There was a direct relationship between average O:N and the ratios of specific activity of the digestive enzymes amylase and trypsin. Species displaying low O:N and/or A:T ratios such as P. fera, C. pachydactyla and Oncaea venusta probably metabolize proteins more efficiently than they do plant carbohydrates (high nitrogen excretion and low amylase activity). Species displaying high O:N and A:T ratios, such as U. darwini, E. marina and T. dicaudata (low nitrogen excretion and high amylase activity) were assumed to use carbohydrates (starch) and proteins with equal efficiency. S. bradyi showed a large range of variations in trypsin activity and low amylase activity, resulting in a low average A:T ratio, but its O:N ratio was intermediate. Variations in O:N and O:P ratios were related to differences in the nutritional strategy of the different species, based on literature data concerning the anatomy of their mouth parts and their selectivity for animal material in mixed-food experiments.
Patent•
16 May 1983
TL;DR: In this article, enocyanin extracts, known as enocianina, extracted from grape pomace with sulphure dioxide, are treated with enzymes, e.g. pectinase and amylase, to reduce or remove solids from the extract.
Abstract: Anthocyanin extracts, known as enocianina, extracted from grape pomace with sulphure dioxide, are treated with enzymes, e.g. pectinase and amylase, to reduce or remove solids from the extract. The colour of the enocianina can be intensified by treatment of the clarified extract with acetaldehyde.
TL;DR: The fruits picked at 85 days after fruit set stored better, with lower fruit weight loss, less fungal spoilage and superior quality, whereas tannins, starch and vitamin C decreased during storage.
TL;DR: Determination of isoamylases is a more sensitive index to acute pancreatitis than lipase assay and may be particularly useful when pancreatitis is suspected despite a normal total amylase activity.
Abstract: We compare the clinical value of assay of amylase (EC 3.2.1.1) isoenzymes with that of lipase (EC 3.1.1.3) in serum from patients with proven acute pancreatitis or with hyperamylasemia from other causes. In the former group we measured amylase, lipase, and isoamylases daily. Lipase and P(pancreas)-type isoamylases reached the highest mean values on the first day of an attack of acute pancreatitis (day one). Lipase declined rapidly, and by day four its mean activity was about the same as that of amylase and lower than that of the P-type isoamylases. Great inter-individual variations were found among patients with a similar clinical course. Of the 85 samples analyzed, amylase activity for 36 declined to within reference limits, but 18 of the 36 had high lipase activity, 18 had high P-type isoamylases activity, and 31 had P3 isoenzyme, which is not detectable in normal sera. Determination of isoamylases is a more sensitive index to acute pancreatitis than lipase assay and may be particularly useful when pancreatitis is suspected despite a normal total amylase activity. In the group of patients with hyperamylasemia from other origins, three had macroamylasemia, one had mumps, one had abdominal trauma without pancreatic injury, and one had pelvic inflammatory disease. The specific pattern of macroamylase on electrophoresis permitted a precise diagnosis of macroamylasemia; normal lipase had only ruled out pancreatitis. In the three other cases, lipase and isoamylases excluded pancreatic involvement.
TL;DR: The genetics of α-amylase production in Bacillus subtilis is reviewed and classical and recombinant DNA approaches to increasing α-amide production are discussed.
Abstract: Thermostable α-amylases have application in a variety of industrial processes and enzymes from a substantial number of thermophilic bacteria and fungi have been screened and characterized to varying degrees. The characteristics of these enzymes are summarized in this review. The genetics of α-amylase production inBacillus subtilis is reviewed and classical and recombinant DNA approaches to increasing α-amylase production are discussed.
TL;DR: In this article, the changes in the principal constituents of melon duringogiri production by fermentation were investigated, and the results of the enzymatic activities inogiri are compared with the fermentation of similar vegetable proteins.
Abstract: The changes in the principal constituents of melon duringogiri production by fermentation were investigated. The total nitrogen decreased in the fermentedogiri. The activities of proteinases increased during the fermentation as well as the amounts of amino acids. The amylase activities also increased with fermentation, but the soluble sugars showed a remarkable fluctuation culminating in a peak at 120 h of fermentation. Lipase activity was minimal in the fermenting mash. The results of the enzymatic activities inogiri are compared with the fermentation of similar vegetable proteins.