Showing papers on "Amylase published in 1981"

A Compositional Study of Amaranth Grain

Abstract: The chemical composition of ten amaranth seed samples was determined. The saccharide content was determined using gas chromatography and high performance liquid chromatography. Sucrose was the major sugar followed by raffinose. Inositol, stachyose, and maltose were found in small amounts in most of the samples. Autolysis for 16 hr at pH 5.0 and 6.5 resulted in decreased sucrose and raffinose concentrations. Maltose was liberated by autolysis at pH 6.5 but not at pH 5.0. Inositol increased after autolysis. It was concluded that invertase, amylase, and phytase occur in the grain. Physicochemical properties of isolated amaranthus starch were measured and compared with analogous values reported for wheat starch. The lipids from representative amaranth grain varieties were analyzed for fatty acid composition. Squalene was present in the oil in large amounts, compared to other grains. The amino acid composition of the grain was used to calculate the chemical score (73) and the nitrogen to protein conversion factor (5.85). Leucine was found to be the limiting amino acid. Tannin and vitamin levels typical of other grains were detected. Mineral and proximate compositions were similar to previously reported values.

Pancreatic islet-acinar cell interaction: amylase messenger RNA levels ar determined by insulin

Abstract: Pancreatic amylase messenger RNA progressively decreases in rats rendered diabetic with streptozotocin. Insulin reverses this effect, inducing a selective decrease in amylase messenger RNA in the pancreas. Parotid amylase messenger RNA is not significantly affected by either diabetes or insulin.

Characterization of a Thermostable α‐Amylase from Bacillus licheniformis NCIB 6346

Abstract: With one exception (NCIB 9668), the extracellular amylases from 10 strains of Bacillus licheniformis were thermostable and retained more than 98% of their original activity after incubation at 85°C for 60 min. The enzyme from B. licheniformis NCIB 6346 was purified 30-fold by ion-exchange chromatography and was characterized. It had an endo-action on starch yielding maltopentaose as the major product, and was identified as an α-amylase. The purified enzyme had a molecular weight of 62 650, was stable between pH 7 and 10 and was maximally active at 70-90°C at pH 7.0. It closely resembled commercial thermostable α-amylases in its general properties and it is concluded that B. licheniformis provides a good source of these enzymes.

Effect of Soy Protein, Casein and Trypsin Inhibitor on Cholesterol, Bile Acids and Pancreatic Enzymes in Mice

Abstract: Dietary vegetable proteins may lower plasma cholesterol compared to animal proteins. We considered the possibility that lower digestibility and the trypsin inhibitor (TI) content of plant proteins could lead to alterations in bile acid metabolism and exocrine pancreatic function mediating some of this change. Mice were fed cholesterolemic diets of different protein source and TI content: casein, soy protein isolate, or casein plus TI for 4 weeks. Plasma and liver cholesterol were measured; pancreata, intestinal contents and mucosal scrapes were collected for bile acid, trypsin, chymotrypsin, amylase, and lipase assays. The soy group had lower plasma cholesterol levels. Intestinal bile acids in this group were higher, suggesting a causal relationship (increased bile acid secretion leading to increased cholesterol catabolism). Conversely, liver cholesterol in this group was raised, reflecting a possible shift in body cholesterol pools. TI addition did not affect lipid metabolism, though it did affect pancreatic function: it led to increased pancreatic weight and depressed intestinal trypsin activity, but elevated chymotrypsin and amylase levels in pancreas and intestine and increased trypsin levels in the pancreas. Therefore, soybean TI does not seem to affect cholesterol metabolism, though it greatly affects pancreatic secretion. On the other hand, soy protein has a marked effect on the bile acid and cholesterol metabolism, which may be a function of protein quality.

Serum amylase and lipase activities in the diagnosis of pancreatitis in dogs.

Abstract: To determine the usefulness of information provided by measurement of serum amylase activity in the evaluation of dogs for pancreatitis, the relationship of amylase activity to lipase activity in 713 paired serum samples was investigated by statistical analysis. Little change in mean amylase concentration was found until lipase values exceeded 800 U/L. The ranges of amylase activity (mean +/- 2 SD) were essentially the same for dogs with no pancreatitis (0 to 100 U of lipase activity/L) as for dogs with a high probability for the disease (700 to 799 U of lipase activity/L), 0 to 4,029 U/L and 857 to 4,869 U/L, respectively. Pathologic findings from biopsy and necropsy reports from 92 dogs for which serum lipase determinations were done indicated that serum lipase increased not only with pancreatitis, but also with other medical problems, such as renal and hepatic disease. It was concluded that determination of serum amylase activity without knowledge of serum lipase activity was of little value to diagnose pancreatitis. High amylase activity was not specific for pancreatitis and low amylase activity could not rule out the disease. The results of this study also showed that low serum lipase values almost always eliminated the possibility of pancreatitis and that high values were often, but not always, diagnostic for pancreatitis.

Comparative study of amylolytic enzymes production byAspergillus niger in liquid and solid-state cultivation

Abstract: Amylolytic enzymes produced by a strain ofAspergillus niger cultivated on cassava starch in liquid or solid culture were found to be mainly glucoamylases. For the same initial amount of substrate, the glucoamylase activity increased even after 60 h of culture on solid medium whereas it decreased in liquid culture. Some characteristics of the amylases produced in both culture conditions were compared. The pH optima for enzymes produced in solid and liquid cultures were 4.5 and 5.0 respectively. Glucoamylase synthetized in solid cultures was significantly more thermostable than that from liquid culture and was maximally active at 70°C compared to 50°C for the enzyme from liquid cultures. The Km values expressed as mg soluble starch/100 ml were 0.1% for crude enzyme from solid culture and 0.057% for crude enzyme from liquid culture.

PURIFICATION AND CHARACTERIZATION OF AN α‐AMYLASE INHIBITOR FROM MAISE (ZEA MAIZE)

Abstract: α-Amylase inhibitor is presented in maize seeds. It is a protein as indicated by precipitation with ammonium sulfate and trichloroacetic acid, denaturation by heat, digestion with proteases and by dye-staining. It was purified to homogeneity by ammonium sulfate precipitation and Sephadex G-75 gel filtration. It had an apparent molecular weight of 29,600 and did not contain any carbohydrate. Its properties differed from those of previously reported α-amylase inhibitors, since it was active against α-amylase of maize, produced during germination as well as against Bacillus subtilis α-amylase. It was also active against α-amylase from the insects Tribolium castaneum, Sitophilus zeamais and Rhyzopertha dominica, but it was inactive against α-amylase from human saliva, hog pancreas, Aspergillus oryzae, wheat, rye, barley, triticale, and sorghum. It was stable for 5 min at 96°C at pH 7. Maximal inhibition required at least 10 min of preincubation with the enzyme at pH 6.8 and 257deg;C. Polyacrylamide gel electrophoresis gave three protein bands, but only one was obtained in S.D.S. and mercaptoethanol.

Effect dietary corn starch intake on pancreatic amylase and intestinal maltase and pH in cattle.

Abstract: The pH optimum of pancreatic alpha-amylase from grain-fed steers was determined to be 6.9, while that of intestinal maltase was established at 5.8. Both assays were found to be linear up to 1 hr of incubation. The V max of pancreatic amylase was determined to be pancreatic amylase was determined to be 1.15 mg of maltose monohydrate produced/hr. Activities of pancreatic and intestinal maltase were not reduced (P greater than .05) during the interval from sample collection from the animal until analysis 4 hr later when tissues were kept on ice. Twenty-four yearling Holstein steers fed either alfalfa hay at a maintenance level of metabolizable energy (ME) intake or corn at one, two or three times the maintenance ME intake level were slaughtered after being fed 106 days. The pancreas was removed alone with sections of the intestine. Specific activity of pancreatic amylase for steers fed the high level of corn was 129% of that for steers fed the alfalfa diet (P greater than .05). Intestinal maltase activity was highest in the jejunum and decreased toward the ileum. Increasing dietary starch intake resulted in no response (P greater than .05) in maltase activity at 10, 30, 50, 70, or 90% of the small intestine length. The effect of dietary starch level on dieesta pH was dependent on sampling location within the small intestine. There were no dietary effects (P greater than .05) on digesta pH for the first 10% segment of intestine distal to the pylorus. However, in all subsequent sections, digesta pH was higher steers fed the alfalfa diet than for those fed the two higher levels of grain. A calculation for estimating th amount of pancreatic amylase needed to hydrolyze starch presented to small intestine is discussed.

New Enzyme System-Beta-Amylase-Pullulanase-To Determine the Degree of Gelatinization and Retrogradation of Starch or Starch Products

Abstract: A sensitive method to determine the change of degree of gelatinization during storage of starch products was studied. A new enzyme system consisting of beta-amylase-pullulanase was established for this purpose and named as BAP method. Beta-amylase is known not to react on raw starch and pullulanase is also known to be strongly affected by the degree of dispersion of amylopectin molecule in a solution. The new enzyme system clearly differentiates the velocity of hydrolysis between gelatinized starch and retrograded one compared with the conventional glucoamylase system. This enzyme system is particularly useful to determine the retrogradation of starchy food during storage.

Studies on the carbohydrases in the digestive tract of the milkfish chanos chanos

Abstract: Crude extracts from various regions of the digestive tract of pond grown milkfish were tested forttheir ability to catalyze the hydrolysis of various carbohydrates. The most active carbohydrases were those involved in the hydrolysis of α-glucosidic bonds. Maltose, trehalose, dextrin, starch and glycogen were rapidly hydrolyzed in the presence of crude extracts from the intestines and the pyloric caeca. High amylase activity was observed in extracts from the intestines, pancreas, pyloric caeca and liver. The intestinal amylase had optimum activity at pH 6.2 and at a temperature of about 50°C. It was active at a chloride concentration of 10 to 40 ppt. The amylase activity in the intestines consistently peaked daily at about noon when the milkfish gut was full. In contrast, enzyme activity was significantly lower at 0030 hrs when the gut was empty. These results are consistent with earlier observations that the milkfish is a daytime feeder and suggest further that intestinal amylase secretion is in phase with the feeding activity of the milkfish. Although the fishes used in this study fed mostly on the naturally occurring algae in the ponds, no cellulase activity was detected in any region of the digestive tract. Less active carbohydrases that were detected include a β-glucosidase and β-galactosidase, both of which were of limited substrate specificity.

Genetically engineered microorganisms for massive production of amylolytic enzymes and process for preparing same

Abstract: Genetically engineered microorganisms are provided which contain recombinant DNA with an amylase coding gene. Improved yields of amylase enzymes are obtained by cultivating these microorganisms.

Phosphorylation of the same specific protein during amylase release evoked by beta-adrenergic or cholinergic agonists in rat and mouse parotid glands

Abstract: Stimulation of amylase secretion from the rat parotid gland by beta-adrenergic agonists is associated with a specific phosphorylation of three membrane-bound proteins designated as proteins I, II, and III [Jahn, R., Unger, C. & Soling, H. D. (1980) Eur. J. Biochem. 112, 345-352]. In contrast, stimuliation by carbachol induced significant phosphorylation of only protein I. This phosphorylation was low compared to isoproterenol-induced phosphorylation but corresponded to the smaller enhancement of amylase secretion. The mouse organ, however, is almost equally sensitive to beta-adrenergic and to cholinergic agonists. Incubation of mouse parotid gland slices with either 20 microM isoproterenol or 10 microM carbachol resulted in strong and comparable releases of amylase, which were accompanied by comparable phosphorylations of protein I. Proteins II and III were phosphorylated only in the presence of isoproterenol. Removal of external calcium by ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetate abolished the carbachol-induced release of amylase but not the phosphorylation of protein I. Isoproterenol-induced secretion of amylase and phosphorylation of proteins I, II, and III were not inhibited under these conditions. Amylase release stimulated by the ionophore A-23187 was accompanied by the phosphorylation of protein I. Two-dimensional electrophoresis revealed that the radioactive spot corresponding to protein I was located at the same position after cholinergic and after beta-adrenergic stimulation, indicating that both stimuli led to the phosphorylation of the same membrane-associated protein. These findings strongly support the view that the phosphorylation of protein I is an important step in the sequence of events leading from receptor activation to exocytosis.

Oligostatins, new antibiotics with amylase inhibitory activity. I. Production, isolation and characterization.

Abstract: Oligostatins C, D and E, three new antibiotics were found in the culture filtrate of Streplomyces my.vogenes nov. sp. SF-1130. Their spectral and chemical properties suggested that oligostatins were basic oligosaccharide antibiotics. They exhibited not only antibacterial activity but also strong amylase inhibitory activity.

Actions of a newly isolated intestinal peptide PHI on pancreatic acini.

Abstract: In dispersed acini from guinea pig pancreas, PHI, a peptide recently isolated from porcine intestine and found to contain 27 amino acids, inhibited binding of 125I-vasoactive intestinal peptide (125I-VIP), increased cellular cAMP, and stimulated amylase secretion. The increase in amylase secretion caused by a maximally effective concentration of PHI in combination with 8-bromo-cAMP, VIP, or secretin was the same as that caused by PHI alone. In contrast, the increase in amylase secretion caused by PHI plus bombesin, carbachol, or the C-terminal octapeptide of cholecystokinin was significantly greater than the sum of the increase caused by each secretagogue acting alone. From the abilities of PHI to inhibit binding of 125I-VIP, to increase cellular cAMP, and to increase amylase secretion, the apparent affinity of PHI for the VIP-preferring receptors on pancreatic acinar cells is approximately 25 times less than that of VIP but 10 times greater than that of secretin. From the ability of PHI to increase cellular cAMP, the apparent affinity of PHI for the secretin-preferring receptors on pancreatic acinar cells is approximately 300 times less than that of secretin but equal to that of VIP.

Process for the preparation of a hydrolyzed product from whole grain and such a product

Abstract: The present invention relates to a process for the preparation of hydrolyzed products from whole grain, and such derived products. The invention solves the problem of obtaining a protein and sugar containing product able to be filtrated whereby this is achieved by treating whole grain, as wheat, maize, rye, barley, oat, and rice, with a proteolytic enzyme to transform waterinsoluble proteins into watersoluble products, and further to treat the starch contents with an amylase free from other carbohydrate hydrolyzing enzymes to form watersoluble starch products, as mono and disaccharides, removing the bran fraction and removing water to obtain a dry, semimoist, or liquid but concentrated derived product. The product is to be added as a sweetening agent in food products as bread, drinks, and cereal products, whereby the bran obtained can be used in bread as fiber additive.

Cereal β-amylase: Immunochemical study on two enzyme-deficient inbred lines of rye.

Abstract: Two inbred lines of rye (Secale cereale L), the kernels of which displayed a very low level of β-amylase activity (1–3% of the levels generally found in rye), were investigated in comparison with a third normal line. An anti-wheat β-amylase immune serum which cross-reacted with the rye enzyme was used in this study.

Enzymic Mechanism of Starch Breakdown in Germinating Rice Seeds 10. IN VIVO AND IN VITRO SYNTHESIS OF α-AMYLASE IN RICE SEED SCUTELLUM

Abstract: Scutellar tissues were dissected from germinating rice seeds and the incorporation of [35S]methionine into the α-amylase molecule was examined by in vivo and in vitro assay systems. Immunoprecipitation with monospecific anti-α-amylase immunoglobulin G raised against the purified enzyme preparation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography were used to identify α-amylase and its possible precursor molecule. Using freshly prepared scutellar tissues, it was demonstrated that α-amylase is synthesized de novo in the scutellar epithelium and secreted into endosperm. The synthesis of α-amylase directed by the polyadenylic acid-containing ribonucleic acid isolated from the scutellar tissues was also established using the translation system of either wheat germ extract or reticulocyte lysate. The immunoprecipitable product obtained in the in vitro translation system was smaller in molecular weight than that synthesized in vivo on the basis of mobilities in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Results are discussed in relation to the processing of the nascent polypeptide precursor of the enzyme molecule and the introduction of the oligosaccharide chain to the cleaved polypeptide to make up the mature form of α-amylase.

Digestive end products mobilize secretory proteins from subcellular stores in the pancreas

Abstract: Two digestive end products, D-glucose and L-lysine, produced substantial concentration-dependent release of amylase and trypsinogen, respectively, from subcellular storage pools into a postmicrosomal supernatant fraction of rat pancreatic tissue homogenate. This process was selective in that D-glucose did not lead to trypsinogen release, while L-lysine did not effect amylase. An analogue of D-glucose, 2-deoxy-D-glucose, was much less potent than D-glucose on an equimolar basis. Half-maximal release for both end-product enzyme pairs occurred at concentrations within the range of normal plasma values for these end products in the rat. Although amylase release reached an apparent plateau when the concentration of glucose was increased beyond the maximally effective level, lysine concentrations higher than that maximally effective resulted in a fall in trypsinogen release that ultimately returned (at 3.0 mM L-lysine) to the level seen in its absence. When isolated zymogen granules were exposed to the same concentrations of D-glucose or L-lysine, a similar pattern of release was seen, indicating that the zymogen granules are a source of the enzymes released from the particulate phase of the homogenates. These findings can be explained most simply by the selective movement of digestive enzymes across zymogen granule membranes in response to the presence of appropriate end products. They are also consistent with the concept that digestive end products can act rapidly and directly on the pancreatic acinar cell to regulate the mixture of enzymes secreted in response to the specific hydrolytic needs of a meal.

Role of β‐amylase in starch metabolism during soybean seed development and germination

Abstract: Differences in starch metabolism during seed development and germination of two soybean [Glycine max (L.) Merrill] genotypes with normal seed β-amylase activity [‘Williams’ (Sp1b and ‘Altona’ (Sp1b)] and two soybean genotypes with undetectable seed β-amylase activity [‘Chestnut’ (Sp1au) and ‘Altona’ (Sp1)] were investigated. Starch and soluble sugar profiles were essentially the same during seed development and germination. Total amylase activity of Williams and Altona (Sp1b) peaked just prior to seed maturity and then dropped off slowly; whereas, the total amylase activity of Chestnut and Altona (sp1) was very low throughout seed development and germination. The differences in amylase activity between Altona (Sp 1 b) and Altona (sp 1) was also seen in leaves. α-Amylase activity was similar in the four genotypes when β-amylase was inhibited with Hg2+ but was higher in the two genotypes with normal β-amylase activity when β-amylase was inhibited with heat plus Ca2+. Low levels of starch phosphorylase activity were detected throughout seed development and germination, and the activity was similar in three of the genotypes and higher in Altona (sp 1). The protein, oil and oligosaccharide contents of mature seeds of the four genotypes were similar. Altona (sp 1 b) and (sp 1), which appear to be near isogenic lines, were not different in any morphological character or yield. Altona (Sp 1 b) showed greater hydrolysis of soybean seed starch than Altona (sp 1), but the evidence indicates that the mutation resulting in greatly reduced or missing β-amylase activity has no effect on starch metabolism of developing and germinating soybean seeds.

THE EFFECTS OF SUBSTANCE P AND RELATED PEPTIDES ON α-AMYLASE RELEASE FROM RAT PAROTID GLAND SLICES

Abstract: 1 The effects of substance P and related peptides on amylase release from rat parotid gland slices have been investigated. 2 Supramaximal concentrations (1 microM) of substance P caused enhancement of amylase release over the basal level within 1 min; this lasted for at least 40 min at 30 degrees C. 3 Substance P-stimulated amylase release was partially dependent on extracellular calcium and could be inhibited by 50% upon removal of extracellular calcium. 4 Substance P stimulated amylase release in a dose-dependent manner with an ED50 of 18 nM. 5 All C-terminal fragments of substance P were less potent than substance P in stimulating amylase release. The C-terminal hexapeptide of substance P was the minimum structure for potent activity in this system, having 1/3 to 1/8 the potency of substance P. There was a dramatic drop in potency for the C-terminal pentapeptide of substance P or substance P free acid. Physalaemin was more potent than substance P (ED50 = 7 nM), eledoisin was about equipotent with substance P (ED50 = 17 nM), and kassinin less potent that substance P (ED50 = 150 nM). 6 The structure-activity profile observed is very similar to that for stimulation of salivation in vivo, indicating that the same receptors are involved in mediating these responses. 7 All the fragments of substance P tested were capable of eliciting a full amylase release response. This indicates that the apparent partial agonist action of the C-terminal nonapeptide fragment on in vivo salivation is not explicable at the receptor level.