Showing papers on "Amylase published in 1971"
TL;DR: This chapter outlines the recent developments in the amylase field, with a discussion of the emerging fields of biosynthesis and the control of amylases action, and the simplest and the least desirable alkaline oxidation method.
Abstract: Publisher Summary This chapter outlines the recent developments in the amylase field, with a discussion of the emerging fields of biosynthesis and the control of amylase action The International Commission on Enzymes has recommended a standard method for expressing enzymic activity as the number of micromoles of substrate transformed under defined conditions by an enzyme The production of new reducing ends is most frequently followed by the 3,5-dinitrosalicylate, alkaline ferricyanide, or alkaline copper methods, or by oxidation of glucose with glucose oxidase The simplest and the least desirable alkaline oxidation method involves reduction of 3,5-dinitrosalicylate With this method, reducing equivalents for equimolar amounts of substrates increases significantly with increasing chain length Measurements are subject to interference by Ca 2+ used to stabilize amylases and are relatively insensitive It has the advantage of highest sensitivity and precision, low and stable background, and is relatively insensitive to a wide range of contaminating substances Ironically, its greatest disadvantage is its high sensitivity leading to high substrate backgrounds This problem can be circumvented by borohydride reduction of the substrate
151 citations
TL;DR: Four proteins, which have been designated A, B, C and D, have been purified from human parotid saliva and showed significant activity in assays for amylase, acid and alkaline phosphatase, protease, lysozyme, ribonuclease, peroxidase, beta-glucuronidase and iron-binding activity.
Abstract: Four proteins, which have been designated A, B, C and D, have been purified from human parotid saliva. These proteins are the major constituents of parotid saliva which migrate rapidly to the anode in polyacrylamide electrophoresis at pH9.5. Gel filtration and polyacrylamide electrophoresis were employed in the purification procedures. After purification all four preparations were tested for homogeneity by electrophoresis at pH2.8 and 9.5, by isoelectric focusing in the pH range 3-10, by immunodiffusion, and by sedimentation in the analytical ultracentrifuge. None of the proteins showed significant activity in assays for amylase, acid and alkaline phosphatase, protease, lysozyme, ribonuclease, peroxidase, beta-glucuronidase, beta-galactosidase, iron-binding activity and esterase. No cross-reactions were detected with antisera specific for lactoferrin and 15 serum proteins. All four proteins were rich in glutamic acid, proline and glycine and were lacking completely the sulphur-containing amino acids. Proteins A and C contained no threonine or tyrosine. Carbohydrate could be demonstrated only in protein A at a concentration of 4% of the total protein.
144 citations
TL;DR: A β-glucanase-free preparation of amyloglucosidase is employed to hydrolyse starch to glucose; this is subsequently estimated by the glucose oxidase technique.
Abstract: A specific enzyme method is described for the routine estimation of starch in small quantities (10–30 mg) of dried leaf tissue. A β-glucanase-free preparation of amyloglucosidase is employed to hydrolyse starch to glucose; this is subsequently estimated by the glucose oxidase technique. The method gives result which agree closely with those obtained by a specific iodine-precipitation method.
135 citations
TL;DR: In the larvae of the Egyptian cotton worm, Spodoptera littoralis, the optimum for protease activity was found to be a reaction mixture of pH 11·0 plus 0·75% casein at 37°C for 60 min, and for amylase activity the optimum was a reaction mix of pH 9·5 plus0·25% starch at 37 °C for 30 min.
127 citations
TL;DR: An extracellular amylase from Pseudomonas stutzeri was purified over 1000-fold by ammonium sulfate and acetone precipitations, which resulted in the exclusive production of maltotetraose and a high molecular-weight limit dextrin from amylopectin and glycogen.
123 citations
114 citations
TL;DR: Most of the calcium (>80%) present in rat parotid gland slices was secreted concomitantly with the exportable protein, and the secretory granules showed the highest calcium/protein ratio which was identical with that found for the material secreted by the slices.
Abstract: Most of the calcium (>80%) present in rat parotid gland slices was secreted concomitantly with the exportable protein. Detailed kinetics showed that secretion induced by catecholamines and by N6 monobutyryl adenosine 3′:5′-monophosphate proceeded at an approximately constant ratio of calcium to amylase (60 nmoles calcium/mg exported protein). It was calculated that the calcium which is tightly bound to amylase could account for only 11% of the exported calcium.
Among the subcellular fractions of the gland, the secretory granules showed the highest calcium/protein ratio which was identical with that found for the material secreted by the slices. Both amylase and calcium were sedimented in a crude granule fraction to the extent of 50% of the total present in the homogenate of the gland.
Various treatment that caused release of amylase from the crude secretory granule fraction also caused release of calcium to a similar extent. The calcium in secretory granules was not readily exchangeable when the granules were suspended in a medium containing 45Ca. The possible role of calcium in the aggregation of the exportable proteins in the secretory granules is discussed in view of the information on the presence of relatively high concentrations of bivalent cations in some other gland systems.
98 citations
TL;DR: The characteristic point of this microorganism was especially good growth in alkaline media, and no growth was detected in neutral media such as nutrient broth, which indicates this alkaline amylase is a type of saccharifying α-amylase.
Abstract: Bacillus No. A–40–2 isolated from soil produced an alkaline amylase in alkaline media. The characteristic point of this microorganism was especially good growth in alkaline media, and no growth was detected in neutral media such as nutrient broth. The alkaline amylase of Bacillus No. A–40–2 was purified by DEAE-cellulose and hydroxyl apatite columns. The amylase was most active at pH 10.5 and stable pH was about 8.5. Calcium ion was effective to stabilize the enzyme especially at high temperatures. The sedimentation constant was about 3.8 S and molecular weight estimated by the Sephadex gel-filtration method was about 70,000. The enzyme was inactivated by urea, sodium laurylsulfate and sodium dodecylbenzene sulfonate. EDTA, PCMB and DFP did not show inhibitory effect. The enzyme hydrolyzed about 70% of starch and yielded glucose, maltose and maltotriose. If the enzyme is a single entity, this alkaline amylase is a type of saccharifying α-amylase.
85 citations
83 citations
TL;DR: The findings appear to exclude cyclic 3',5'-adenosine monophosphate as an intermediate in the α-receptor response, and show that both α- and β-receptors are present in the same exocrine cell.
Abstract: Epinephrine caused amylase secretion and K+ release in rat parotid slices. Propranolol, which blocks β-receptors, inhibited amylase secretion; phentolamine, which blocks α-receptors, inhibited K+ release. Since enzyme secretion was associated with fusion of secretory granules to the cell membrane and K+ release was associated with vacuole formation, it could be shown that both α- and β-receptors are present in the same exocrine cell. The findings appear to exclude cyclic 3',5'-adenosine monophosphate as an intermediate in the α-receptor response.
78 citations
TL;DR: Adult rats, previously maintained on a chow containing 48 p.
TL;DR: The increased stability of the CM-cellulose-amylase compared with free amylase was demonstrated in the continuous hydrolysis of starch in an ultrafilter reactor.
TL;DR: All four fungi studied attained approximately the same dry weight of mycelium in starch-yeast extract medium, but the initial growth rate of H. grisea var.thermoidea was greater than the other three fungi, and H. lanuginosa produced 8 to 12 times as much as theother three.
Abstract: All four fungi studied attained approximately the same dry weight of mycelium in starch-yeast extract medium. Only about one-fourth the amount of mycelia was produced in yeast extract alone (starch omitted). However, the initial growth rate ofH. grisea var.thermoidea was greater than the other three fungi. Extracellular amylase was produced by all four fungi, butH. lanuginosa produced 8 to 12 times as much as the other three. Maximum extracellular amylase was found before autolysis with these three fungi, but after autolysis withH. lanuginosa. Extracellular amylase was detected in YE medium (lacking starch), but in very low amounts (approximately one-eighth the amount observed as when starch was present). Increasing the amount of starch in the medium increased extracellular amylase. However, when the starch concentration was kept constant, increasing the concentration of yeast extract had no effect on extracellular amylase.
TL;DR: Adult carp showed marked maltase, amylase, and weak sucrase, lactase, melibiase, cellobiase and methyl-α-D-glucosidase activities in the intestine and young carp showed the activities of weak trypsin-like enzyme and maltase in the pharynx.
Abstract: The activities of various kinds of carbohydrases in the digestive organs of several fishes were determined with TAUBER-KLEINER's method modified by the authors. The results obtained were as follows. Adult carp showed marked maltase, amylase, and weak sucrase, lactase, melibiase, cellobiase and methyl-α-D-glucosidase activities in the intestine. The activities of maltase and amylase in adult carp intestine were highest in distal part while that of sucrase was highest in central part. The specific activities of maltase and amylase in young carp intestine were higher than those in adult carp. Young carp also showed the activities of weak trypsin-like enzyme and maltase in the pharynx, and fairly high activities of trypsin-like enzyme, mal-tase and amylase in the esophagus. Even carnivorous fish such as red sea bream and marine ayu showed considerable activities of maltase in their digestive tract.
TL;DR: It is suggested that the renal excretion of amylase results from glomerular filtration without appreciable tubular reabsorption, and the disproportionate elevation of the urinary amylases excretion rate relative to the serum amyl enzyme level in acute pancreatitis.
Abstract: Pure amylase was isolated from pancreata and parotid glands of the baboon, an animal which has a serum amylase level and renal clearance of amylase (C(Am)) similar to man. After bolus injection, both pancreatic and salivary amylase rapidly disappeared from the serum in a monoexponential fashion with a mean serum half-time of approximately 83 min. Only about 24% of the amylase cleared from the serum appeared in the urine indicating that the majority of amylase was removed from the serum by an extraurinary mechanism. The C(Am) by the kidney was constant over a wide range of serum amylase levels and the ratio of C(Am)/C(In), which averaged 3.0%, was not influenced by mannitol diuresis. This suggests that the renal excretion of amylase results from glomerular filtration without appreciable tubular reabsorption. Pancreatic amylase was consistently cleared more rapidly by the kidney than was the baboon's endogenous amylase while salivary amylase was consistently cleared less rapidly than endogenous amylase. THE FINDINGS IN THIS STUDY PROVIDE INSIGHT INTO SEVERAL OF THE FOLLOWING CLINICALLY OBSERVED PHENOMENA: (a) the short serum half-time of amylase accounts for the transient nature of serum amylase elevations in pancreatitis; (b) the extra-urinary removal of amylase accounts for the maintenance of relatively normal amylase levels in uremia; and (c) the more rapid renal clearance of pancreatic amylase compared to salivary amylase may explain the disproportionate elevation of the urinary amylase excretion rate relative to the serum amylase level in acute pancreatitis.
TL;DR: C. chinensis larval amylase is activated by Ca(2+) and inhibited by Cl(-) and EDTA and the inhibition by iodoacetic acid and N-ethylmaleimide suggest that free thiol groups are essential for activity.
Abstract: C. chinensis larval amylase is activated by Ca(2+) and inhibited by Cl(-) and EDTA (K(i) 6.7x10(-3)m). GSH and 2-mercaptoethanol activate, presumably at different sites, as 2-mercaptoethanol interferes with Ca(2+) activation, whereas GSH enhances it. The inhibition by iodoacetic acid and N-ethylmaleimide (K(i) 1.55x10(-2)m) suggest that free thiol groups are essential for activity. The pH optimum of 5.2-5.4 is moved to 5.6-5.8 by Ca(2+) and 2-mercaptoethanol. The activation energy is 7270 cal/mol, and is not affected by Ca(2+) and 2-mercaptoethanol. K(m) for soluble starch is 2.3mg/ml.
TL;DR: A large number of bacterial and mold amylases have been isolated in crystalline form from various sources, including Bacillus subtilis α -amylase was the first to be crystallized as discussed by the authors.
Abstract: Publisher Summary Bacterial and mold amylases have been the objects of organic chemical and physicochemical studies as they are available in large quantities and can be easily purified and crystallized. A large number of bacterial and mold amylases have been isolated in crystalline form from various sources. Bacillus subtilis α -amylase was the first to be crystallized, which was later followed by B. subtilis , Aspergillus oryzae , B. coagulans , A. candidus , Pseudomonas saccharophila , B. polymyxa , B. macerans , A. niger , B. amyloliquefaciens , and B. stearothermophilus . Crystallization of amylases requires the presence of divalent cations, especially calcium ions. When crystallization is repeated, it becomes increasingly difficult as loss of the cations results in apparent high solubility of the enzymes. Most of the crystalline amylases have been shown to be homogeneous in sedimentation and electrophoretic analysis. It was found, however, that even after repeated crystallization, crystalline Taka-amylase A is still contaminated by traces of proteases that can only be removed by chromatography. Polyacrylamide gel electrophoresis and analytical ion exchange chromatography are used to examine the homogeneity of an amylase preparation. It has been shown by polyacrylamide gel electrophoresis that crystalline amylases from B. macerans , B. amyloliquefaciens , B. stearothermophilus , and A. oryzae are homogeneous.
TL;DR: It is proposed that the over-all effect of gibberellic acid on enzyme development is to provide more substrate (particularly glucose) for general cell metabolism and wall synthesis within elongating internodes.
TL;DR: In the isolated cat pancreas, stimulated maximally with secretin, increasing the perfusate potassium concentration (at the expense of sodium ions) caused a copious secretion of amylase from the gland, reduced the volume rate of secretion and caused vasoconstriction.
Abstract: 1. In the isolated cat pancreas, stimulated maximally with secretin, increasing the perfusate potassium concentration (at the expense of sodium ions) caused a copious secretion of amylase from the gland, reduced the volume rate of secretion and caused vasoconstriction.
2. Rubidium and caesium had similar effects to potassium: lithium, though depressing secretory rate, had no effect on enzyme secretion or vasoconstrictor action.
3. Amylase secretion was detected at potassium concentrations of 30 m M and was maximal at 80–90 m M, output declining as the concentration was raised to 120 m M.
4. Amylase secretion was maximal during the first few minutes of exposure to excess potassium, but remained above basal levels throughout the test period. Secretory rate was depressed by a constant amount during the test period.
5. Atropine sulphate blocked the effect on enzyme secretion without affecting the reduction in secretory rate.
6. During perfusion with excess potassium a vasodepressor material with the properties of acetylcholine was detected in the effluent from the gland.
7. The reduction in secretory rate, when perfusate sodium was replaced by potassium, was equal to that obtained when sodium was replaced by sucrose.
8. It is concluded that potassium stimulates amylase secretion indirectly by releasing acetylcholine from nerve terminals in the gland, and that the reduction in secretory rate is due not to excess potassium but to sodium deficiency.
TL;DR: A reliable method is presented for rapidly screening human sera to detect macroamylasemia, and Macroamylase, if present, is found in the blue-colored fractions, while amylase of normal molecular weight appears in the fractions colored by cytochrome c.
Abstract: A reliable method is presented for rapidly screening human sera to detect macroamylasemia. A mixture of the serum to be tested, Blue Dextran, and cytochrome c is filtered through a small column of cross-linked dextran gel (Sephadex G-100). Amylase in the effluent fractions is detected by incubation with amylose and subsequent addition of iodine. Macroamylase, if present, is found in the blue-colored fractions, while amylase of normal molecular weight appears in the fractions colored by cytochrome c.
Journal Article•
TL;DR: The enzyme resembles pullulanase [bacterial R-enzyme, EC 3.2.1.9] from Aerobacter aerogenes, and the in vivo significance of this enzyme is discussed.
TL;DR: Pancreatic enzyme secretion in rats anesthesized by pentobarbital was stimulated by intravenous perfusion of the hormone pancreozymin, as indicated by a decreased amylase level in the pancreas and by specific, fine structural changes observed in an electron microscope.
Abstract: Pancreatic enzyme secretion in rats anesthesized by pentobarbital was stimulated by intravenous perfusion of the hormone pancreozymin, as indicated by a decreased amylase level in the pancreas and by specific, fine structural changes observed in an electron microscope. Rates of protein synthesis were determined by pulse labeling. Amylase, total protein, and valine were purified from pancreas and counted. Pancreozymin promotes an 8 to 10 times increase in the rate of biosynthesis of pancreatic enzymes, as compared to rats similarly anesthesized but without hormone. This stimulation effect is obtained very rapidly (2 hr) and is not inhibited by actinomycin D. Secretin alone has no effect, whereas pentobarbital is inhibitory.
TL;DR: The results indicate that the amylase regularly present in serum and urine is not of pancreatic origin, and only those elevated amounts ofAmylase which appear in the urine and blood under pathological conditions are derived from the pancreas.
TL;DR: A starch substrate film technique was used to determine the localization and onset of amylase activity in the major salivary glands of mice, and the submandibular gland exhibited the sexual dimorphism that has been characterized for the adult gland.
Abstract: A starch substrate film technique was used to determine the localization and onset of amylase activity in the major salivary glands of mice. The earliest activity occurred in the parotid gland of males and females at 8 days of age. The intensity of the reaction rapidly increased so that by day 16 the entire parotid gland was amylase-positive. The submandibular gland exhibited the sexual dimorphism that has been characterized for the adult gland. Amylase activity was observed in the male at 24 days of age, shortly after the first morphologic differences between the submandibular glands of males and females became apparent. The female showed positive results at 36 days of age. Amylase activity in the submandibular glands was localized to the convoluted tubules. As the gland developed, the amylase activity increased in correlation with the increasing concentration of these tubules. The sublingual gland was always amylase-negative.
TL;DR: The view that the liver is the major source of serum amylase in the normal rat is supported, as it showed isoamylases of the pancreatic type appeared in the serum and urine only after ligation of the commone bile duct.
TL;DR: In addition to releasing hydrolytic enzymes, isolated barley aleurone layers release large amounts of reserve protein, which is only partially dependent on gibberellic acid (GA3).
Abstract: In addition to releasing hydrolytic enzymes, isolated barley aleurone layers release large amounts of reserve protein. This protein release is only partially dependent on gibberellic acid (GA3). The addition of GA3 causes a shift in molecular weight distribution to lower molecular weight, and a change in the N-terminal profile of the released protein. Inhibition of proteolysis reduces protein release. When proteolysis is inhibited, amylase production can be made partially dependent on added amino acids.
TL;DR: Amylase activities were related to the degree of liver dysfunction, and serum amylase decreased as the bilirubin and turbidity values increased.
Abstract: Serum amylase activity was measured in 15 normal persons and in 60 liverdisease patients. Impairment of liver was assessed by serum bilirubin and thymol turbidity values. Most of the patients had serum amylase values that were well below the normal limits. Amylase activities were related to the degree of liver dysfunction, and serum amylase decreased as the bilirubin and turbidity values increased.