Showing papers on "Amylase published in 1982"
TL;DR: In vivo Evidence Strongly Suggesting that the [3-P-glycerate]l[P,] Regulates Leaf Starch Synthesis is suggested.
Abstract: INTRODUCTION . REGULATION OF STARCH SYNTHESIS IN ALGAE, CYANOBACTERIA, AND LEAVES . . ...... . . . In vivo Evidence Strongly Suggesting that the [3-P-glycerate]l[P,] Regulates Leaf Starch Synthesis . Regulation of ADPglucose Pyrophosphorylase from Nonchlorophyllous Plant Tissue . Native and Subunit Molecular Weight of the ADPglucose Pyrophosphorylase ....... . SYNTHESIS OF STARCH FROM SUCROSE IN RESERVE TiSSUES . Properties of Sucrose Synthase . . SYNTHESIS OF SUCROSE IN PLANTS . Properties and Regulation of Sucrose-P Synthase . Sucrose-6-Phosphate Phosphatase . Localization of Sucrose Synthesis and Questions Concerning Partition of Photosynthetic Carbon Between Sucrose and Starch . DEGRADATION OF STARCH . Localization of Starch Degradative Enzymes in Leaves. . Properties of Leaf Amylases . Properties of the Spinach Leaf Phosphorylases . Pathway of Starch Degradation in Leaves . Regulation of the Leaf Starch Degradative Enzymes .
357 citations
TL;DR: Amylase inhibitor activity (AIA) of chickpea extracts was investigated and showed higher inhibitor activity towards pancreatic amylase than salivary amylases, though clear-cut differences were not observed among- the cultivars.
Abstract: Amylase inhibitor activity (AIA) of chickpea extracts was investigated
usmg pancreatic and salivary amylases. The extracts showed
higher inhibitor activity towards pancreatic amylase than salivary
amylase..Mean values indicated slightly higher inhibitory activity in
desi than kabuli cultivars, though clear-cut differences were..not
observed among- the cultivars. While in vitro starch digestibility of
meal samples indicated no large differences among desi and kabuli
types of chickpea, the mean values of digestibility of- isolated
starches of kabuli -types wasp higher than those -of desi types: The
mean values of stachyose were higher in desi cultivars. When desi
and kabuli types were considered together, stachyose- and raffmose
contents were not found significantly related to the concentrations
of total soluble sugars while stachyose showed a significant correlation
with raftinose.
190 citations
TL;DR: It is assumed that the inhibitory effects of the fiber on enzymes are attributed inter alia to effects on viscosity, pH, and adsorption, and further that gastric acidification of fiber and conditions lowering intestinal pH may enhance these effects.
169 citations
TL;DR: A partial EcoRI fragment of Bacillus coagulans DNA cloned in an Escherichia coli K12 bacteriophage λ host-vector system was shown to direct the synthesis of a thermostable α-amylase whose activity could be detected in situ on petri plates using the iodine staining method.
Abstract: A partial EcoRI fragment of Bacillus coagulans DNA cloned in an Escherichia coli K12 bacteriophage lambda host-vector system was shown to direct the synthesis of a thermostable alpha-amylase whose activity could be detected in situ on petri plates using the iodine staining method. A 3.31 kb EcoRI fragment containing the active gene with its own promoter was subcloned in pBR322; in the new clone, called pAMY2, the amylase was shown to accumulate in the periplasmic space. The molecular weight of the enzyme, confirmed by in vivo labelling of plasmid products in minicells, was estimated to be 60000. The restriction map of the plasmid was determined for five restriction enzymes and two new plasmids with smaller DNA inserts were constructed, both directing the synthesis of amylase; one of them with a 2.2 kb PstI insert was shown to be responsible for the synthesis of a fused beta-lactamase-alpha-amylase protein with amylase activity.
147 citations
TL;DR: The extracellular amylolytic enzymes of Schwanniomyces alluvius were studied to determine future optimization of this yeast for the production of industrial ethanol from starch as mentioned in this paper.
Abstract: The extracellular amylolytic enzymes of Schwanniomyces alluvius were studied to determine future optimization of this yeast for the production of industrial ethanol from starch. Both alpha-amylase and glucoamylase were isolated and purified. alpha-Amylase had an optimum pH of 6.3 and was stable from pH 4.5 to 7.5. The optimum temperature for the enzyme was 40 degrees C, but it was quickly inactivated at temperatures above 40 degrees C. The Km for soluble starch was 0.364 mg/ml. The molecular weight was calculated to be 61,900 +/- 700. alpha-Amylase was capable of releasing glucose from starch, but not from pullulan. Glucoamylase had an optimum pH of 5.0 and was stable from pH 4.0 to greater than 8.0. The optimum temperature for the enzyme was 50 degrees C, and although less heat sensitive than alpha-amylase, it was quickly inactivated at 60 degrees C. Km values were 12.67 mg/ml for soluble starch and 0.72 mM for maltose. The molecular weight was calculated to be 155,000 +/- 3,000. Glucoamylase released only glucose from both soluble starch and pullulan. S. alluvius is one of the very few yeasts to possess both alpha-amylase and glucoamylase as well as some fermentative capacity to produce ethanol.
128 citations
TL;DR: In this paper, a new method was described for determining the starch content of cereal products, which involves the solubilization of starch with a thermostable α-amylase followed by the complete hydrolysis with an amyloglucosidase.
Abstract: A new method is described for determining the starch content of cereal products. It involves the solubilization of starch with a thermostable α-amylase followed by the complete hydrolysis with an amyloglucosidase. The glucose is then determined by the hexokinase/glucose-6 phosphate dehydrogenase procedure. By using an α-amylase at high temperature, an autoclave is not required to gelatinize and solubilize the starch prior to amyloglucosidase treatment. α-Amylase is added to the sample before heating and degradation begins as soon as the gelatinization temperature is reached, before retrogradation can occur. The procedure was found to be superior to either treatment with acid or alkali, methods which also do not require an autoclave.
124 citations
TL;DR: It is concluded that starch-blocker tablets do not inhibit the digestion and absorption of starch calories in human beings.
Abstract: It has been known for more than 25 years that certain plant foods, such as kidney beans and wheat, contain a substance that inhibits the activity of salivary and pancreatic amylase. More recently, this antiamylase has been purified and marketed for use in weight control under the generic name "starch blockers." Although this approach to weight control is highly popular, it has never been shown whether starch-blocker tablets actually reduce the absorption of calories from starch. Using a one-day calorie-balance technique and a high-starch (100 g) meal (spaghetti, tomato sauce, and bread), we measured the excretion of fecal calories after normal subjects had taken either placebo or starch-blocker tablets. If the starch-blocker tablets had prevented the digestion of starch, fecal calorie excretion should have increased by 400 kcal. However, fecal calorie excretion was the same on the two test days (mean +/- S.E.M., 80 +/- 4 as compared with 78 +/- 2). We conclude that starch-blocker tablets do not inhibit the digestion and absorption of starch calories in human beings.
110 citations
TL;DR: The authors showed that consumption of wheat bran can lead to changes in the exocrine pancreas, perhaps associated with shifts in gut hormones, and may effect absorption by increasing the bulk of material as well as enhancing mucus production in the intestine.
Abstract: Rats were fed a fiber-free (FF) mixture or the same diet with a supplement of 20% wheat bran (WB). After 2 weeks, the pancreas contained higher levels of amylase and trypsin in rats fed WB. In response to a meal, the intestine contained more lipase activity in the WB group. The dry weight of material and protein level in the intestinal contents were also elevated in the WB group. The size of the intestinal villi had not changed, but it did contain more goblet cells. The results indicate that consumption of wheat bran can lead to changes in the exocrine pancreas, perhaps associated with shifts in gut hormones, and may effect absorption by increasing the bulk of material as well as enhancing mucus production in the intestine.
89 citations
TL;DR: The findings imply that carotenoids are physiologically active compounds with specific metabolic processes and are not inert substances swept along with lipids as is commonly assumed from the ability to grow apparently healthy birds free of carotanoids.
85 citations
TL;DR: Under incubation conditions identical to those employed for measuring biological functions, the binding of 125I-BH-CCK to receptors in acini was rapid and reversible and competition-inhibition curves and Scatchard plots of equilibrium binding were compatible with two orders of binding sites.
Abstract: Cholecystokinin (CCK) was conjugated to 125I-Bolton-Hunter reagent (125I-BH-CCK), and the binding of this ligand to CCK receptors in isolated mouse pancreatic acini was correlated with the regulation by CCK of both amylase release and the transport of 2-deoxyglucose and alpha-aminoisobutyric acid. Stimulation of amylase release by CCK was biphasic. At low CCK concentrations (less than 200 pM), amylase release was progressively stimulated, whereas at higher CCK concentrations (greater than 200 pM), amylase release was progressively reduced. In contrast, stimulation of 2-[3H]deoxyglucose transport and inhibition of alpha-[3H]aminoisobutyric acid transport were monophasic, being one-half maximal at 0.85 and 0.44 nM, respectively. Under incubation conditions identical to those employed for measuring biological functions, the binding of 125I-BH-CCK to receptors in acini was rapid and reversible. Competition-inhibition curves and Scatchard plots of equilibrium binding were compatible with two orders of binding sites. Employing a computer program for analysis of multiple binding sites, a high-affinity, low-capacity binding component having a Kd of 26 pM and a lower-affinity, higher-capacity binding component having a component Kd of 2.2 nM were resolved. Regulation of 2-[3H]deoxyglucose and alpha-[3H]aminoisobutyric acid uptake appeared, therefore, to be the result of fractional occupancy of the lower-affinity CCK receptors. Regulation of amylase released was more complex and appeared to be due to the concomitant occupancy of both the high- and low-affinity CCK receptors.
76 citations
TL;DR: Viable, long-lived, gibberellic acid (GA3)-responsive protoplasts have, for the first time, been isolated from aleurone layers of mature wild oat (Avena fatua L.) grain and these respond to treatment with GA3 in essentially the same manner as the tissue from which they were derived.
Abstract: Viable, long-lived, gibberellic acid (GA3)-responsive protoplasts have, for the first time, been isolated from aleurone layers of mature wild oat (Avena fatua L.) grain. More than 90% of the cells of aleurone layers are recovered as protoplasts, and these respond to treatment with GA3 in essentially the same manner as the tissue from which they were derived. Protoplasts become vacuolate during incubation in vitro and, although not dependent upon GA3, vacuolation is markedly stimulated by the hormone. Amylase and ribonuclease (RNase) are produced and secreted only in the presence of GA3 and only after lag periods of 3 d and 4 d respectively. The amounts of amylase produced and secreted are proportional to GA3 concentrations as low as 1.61·10-13 M. With increasing concentrations of mannitol in the culture medium both vacuolation and the GA3-induced production and secretion of enzymes are inhibited progressively, the latter being precluded by 0.6 M to 0.7 M mannitol.
TL;DR: The identification of maltose and beta-limit dextrin as hydrolytic end-products confirmed that these alfalfa root amylases are all beta-amylases.
Abstract: Amylase was found in high activity (193 international units per milligram protein) in the tap root of alfalfa (Medicago sativa L cv Sonora) The activity was separated by gel filtration chromatography into two fractions with molecular weights of 65,700 (heavy amylase) and 41,700 (light amylase) Activity staining of electrophoretic gels indicated the presence of one isozyme in the heavy amylase fraction and two in the light amylase fraction Three amylase isozymes with electrophoretic mobilities identical to those in the heavy and the light amylase fractions were the only amylases identified in crude root preparations Both heavy and light amylases hydrolyzed amylopectin, soluble starch, and amylose but did not hydrolyze pullulan or beta-limit dextrin The ratio of viscosity change to reducing power production during starch hydrolysis was identical for both alfalfa amylase fractions and sweet potato beta-amylase, while that of bacterial alpha-amylase was considerably higher The identification of maltose and beta-limit dextrin as hydrolytic end-products confirmed that these alfalfa root amylases are all beta-amylasesThe pH optimum for both beta-amylase fractions was 60 Both light and heavy beta-amylases showed normal Michaelis-Menten kinetics, with soluble starch as substrate, and had respectively K(m) values of 59 and 68 milligrams starch per milliliter and V(max) of 640 and 130 international units per milligram protein Arrhenius plots indicated that the energy of activation for the heavy beta-amylase remained relatively unchanged (127 to 130 kilocalories per mole) from 0 to 30 degrees C, whereas the energy of activation for the light amylase increased from 120 to about 280 kilocalories per mole at 87 degrees C as temperature was lowered The light amylase was shown to be inhibited by maltose
TL;DR: The cellulase activity of Mastotermes darwiniensis was present in the salivary glands and in the hindgut when carboxymethylcellulose was used as the substrate, and produced mainly, maltose and maltotriose during the hydrolysis of amylose.
TL;DR: It was found that cholecystokinin-pancreozymin produced a dramatic nonparallel transport of these two enzymes with amylase secretion being augmented to a greater degree than trypsinogen secretion.
Abstract: Previous studies have reported that injection of duodenal extracts from rats fed different meals into the celiac artery of recipient rats elicited the secretion of related pancreatic enzymes. We have been unable to reproduce the enzyme-specific increases in the average output of particular enzymes that were observed but did find changes similar in direction, although not magnitude, to those reported previously. The outputs of amylase and trypsinogen were compared by plotting individual data points and performing a regression analysis on them. The injection of duodenal extracts from lactalbumin hydrolysate-fed rats led to trypsinogen secretion being favored over that of amylase and vice versa for extracts from rats fed a glucose meal. In addition, it was found that cholecystokinin-pancreozymin produced a dramatic nonparallel transport of these two enzymes with amylase secretion being augmented to a greater degree than trypsinogen secretion. The relation between their outputs was curvilinear, i.e., the amylase dominance of secretion became more pronounced as overall enzyme output (not dose of hormone) increased. Thus, this nonparallel secretion does not seem to be the results of a discontinuous switch in the character of enzyme secretion produced by the hormone but a graded effect reflecting the magnitude of the response.
TL;DR: Results indicate that heterogeneity of alpha-amylase isozymes is not due to glycosylation of the enzyme protein but likely to differences in the primary structure of the protein moiety, which altogether support that rice alpha-AMylase Isozymes are encoded by multiple genes.
Abstract: The biosynthetic mechanism of alpha-amylase synthesis in germinating rice (Oryza sativa L. cv. Kimmaze) seeds has been studied both in vitro and in vivo. Special attention has been focused on the glycosylation of the enzyme molecule. Tunicamycin was found to inhibit glycosylation of alpha-amylase by 98% without significant inhibition of enzyme secretion. The inhibitory effect exerted by the antibiotic on glycosylation did not significantly alter enzyme activity.In an in vitro system using poly-(A) RNA isolated from rice scutellum and the reticulocyte lysate translation system, a precursor form of alpha-amylase (precursor I) is formed. Inhibition of glycosylation by Tunicamycin allowed detection of a nonglycosylated precursor (II) of alpha-amylase. The molecular weight of the nonglycosylated precursor II produced in the presence of Tunicamycin was 2,900 daltons less than that of the mature form of alpha-amylase (44,000) produced in the absence of Tunicamycin, and 1,800 daltons less than the in vitro synthesized molecule.The inhibition of glycosylation by Tunicamycin as well as in vitro translation helped clarify the heterogeneity of alpha-amylase isozymes. Isoelectrofocusing (pH 4-6) of the products, zymograms, and fluorography were employed on the separated isozyme components. The mature and Tunicamycin-treated nonglycosylated forms of alpha-amylase were found to consist of three isozymes. The in vitro translated precursor forms of alpha-amylase consisted of four multiple components. These results indicate that heterogeneity of alpha-amylase isozymes is not due to glycosylation of the enzyme protein but likely to differences in the primary structure of the protein moiety, which altogether support that rice alpha-amylase isozymes are encoded by multiple genes.
TL;DR: Investigation of different properties, namely, pH optimum, chloride ions effect and the effect of substrate concentration, revealed that the intestinal tissue amyl enzyme is different from pancreatic amylase.
Abstract: 1. The level and distribution of amylase in the chicken intestine and pancreas in addition to some of their properties were examined. 2. The level of amylase was found to be high in chickens and was present in all parts of the intestine except caeca where only traces were detected. 3. Most of the amylase activity was found in the contents of the jejunal part of the small intestine. This was attributed to the secretion from the intestinal tissue and the pancreas. 4. The investigation of different properties, namely, pH optimum, chloride ions effect and the effect of substrate concentration, revealed that the intestinal tissue amylase is different from pancreatic amylase. 5. As amylase in the intestine was found mainly confined to the jejunal lumenal contents, it is assumed that the jejunum is the major site of starch digestion in chickens.
TL;DR: Though all strains tested showed repression of enzyme activity by simple sugars, the degree of repression varies between strains, and in those strains which carry a duplication of the amylase structural gene, the two isozymal forms of amyl enzyme can be differentially repressed by dietary sugars.
Abstract: The level of amylase activity in larvae and adults of Drosophia melanogaster is dependent on the dietary carbohydrate source; flies or larvae from a food medium containing starch show higher levels of activity than individuals from a food containing simple sugars. This is shown to be due to repression of activity by sugars rather than enhancement of activity by starch. Moreover, the changes in enzyme activity reflect a change in enzyme quantity rather than a change in catalytic efficiency. The seeming stimulation of amylase activity by sucrose in some experiments is due, simply, to comparisons with “starvation” diets which cause a large nonspecific reduction in enzyme activity. Though all strains tested showed repression of enzyme activity by simple sugars, the degree of repression varies between strains. Also, in those strains which carry a duplication of the amylase structural gene, the two isozymal forms of amylase can be differentially repressed by dietary sugars.
TL;DR: Analysis of exocrine pancreatic enzymes in the small intestine showed co-lipase deficiency, while amylase, chymotrypsin, trypsin and lipase were normal, and infusion of purified co- Lipase improved fat digestion measured by the triolein breath test.
Abstract: Two normally developed Assyrian brothers with isolated pancreatic co-lipase deficiency are described. They presented at the age of 5-6 years with loose stools. They had steatorrhoea, and analysis of exocrine pancreatic enzymes in the small intestine showed co-lipase deficiency, while amylase, chymotrypsin, trypsin and lipase were normal. Intraduodenal infusion of purified co-lipase improved fat digestion measured by the triolein breath test. Their steatorrhoea diminished on treatment with enteric-coated pancreatic enzymes.
TL;DR: The use of polyethylene glycol 6000 to distinguish macroamylase from normal-sized serum amylase provides a rapid, simple, and accurate means of determining if macroamyasemia is the cause of hyperamylasemia.
TL;DR: The adaptation of the activity of the digestive enzymes of Brycon cf.
Abstract: The adaptation of the activity of the digestive enzymes of Brycon cf. melanopterus (Characidae) to diets were studied. The activity of amylase, trypsin and lipase can be increased respectively with a diet rich in carbohydrate, protein, or fat. Pepsin did not show change in activity.
TL;DR: A bacterium which can utilize potato starch granules as sole carbon source was identified and identified as Bacillus circulans from its physiological and biochemical properties as discussed by the authors, which produces only maltohexaose from gelatinized starch in the early stage of the reaction.
Abstract: A bacterium which can utilize potato starch granules as sole carbon source was isolated and identified as Bacillus circulans from its physiological and biochemical properties. Scanning electron microscopic observation of potato starch granules recovered from the culture broth revealed that granules were degraded gradually from their surface resulting in elongated granules with layered structures on their surface. This bacterium produced extracellular amylase which can digest potato starch granules in vitro. The amylase has a unique property in that it produces only maltohexaose from gelatinized starch in the early stage of the reaction. For the production of this amylase potato starch was found to be most effective while soluble sugars including gelatinized starch and maltose had little effect.
TL;DR: Thermoactinomyces vulgaris α-amylase was purified to an electrophoretically homogeneous state, and its properties and action on starch, pullulan, maltooligosaccharides and partial hydrolyzates ofpullulan were studied.
Abstract: Thermoactinomyces vulgaris α-amylase was purified to an electrophoretically homogeneous state, and its properties and action on starch, pullulan, maltooligosaccharides and partial hydrolyzates of pullulan were studied Both starch-hydrolyzing and pullulan-hydrolyzing activities of the enzyme were inhibited by Al3+, Cu2+, Hg2+, p-chloromercuribenzoate, maltotriitol, panitol, isopanitol and some microbial α-amylase inhibitors to nearly the same extent Km and Vmax values of the enzyme for short chain amylose (DP = 17) and pullulan, Ki values for sugar alcohols and α-amylase inhibitors, and the kinetics of the simultaneous presence of short chain amylose and pullulan supported the view that the hydrolytic action of the enzyme on starch and pullulan is due to a single catalytic site Action patterns of the enzyme on maltooligosaccharides and partially hydrolyzed pullulan were examined, and it was suggested that this α-amylase can attack some of the (1 → 6)-α-d-glucosidic linkages in partial hydrolyzates of pu
TL;DR: It is concluded that dietary fiber of different kinds has the capacity to inhibit pancreatic enzyme activities and the inhibition seems to be more pronounced when exerted in human duodenal juice than in conventional buffer systems.
Abstract: Trypsin, amylase, lipase and phospholipase activities were assayed in buffer solutions and in human duodenal juice after incubation with different types of dietary fiber. In buffer solutions, trypsin
TL;DR: In the rat, pancreatic amylase and, to a lesser extent, lipase adapt quantitatively to the amount of their respective substrates in the diet by an increase in specific activity and total contents, showing that the regulation of the hydrolases may be partly reciprocal and partly independent.
Abstract: In the rat, pancreatic amylase and, to a lesser extent, lipase adapt quantitatively to the amount of their respective substrates in the diet by an increase in specific activity and total contents (range of variation, fivefold for amylase and twofold for lipase). Colipase responded to protein intake (r = 0.85, P less than 0.01) and not to lipids provided protein intake was below 3.5 g or above 6.0 g. With this latter amount of protein, a maximal level was obtained, even with 2% lipid in the diet. Between 3.5 and 6.0 g, lipid intake was found to modulate colipase in parallel with lipase. When different types of fat were compared, the degree of saturation was found to have no impact on lipase, colipase, and amylase. Diets containing medium-chain triglycerides (C8-C10) did not maximally increase specific activity and total content of lipase and colipase, whereas they did not repress amylase as much longer chain triglycerides did. With coconut oil (45% C12), lipase was maximally stimulated but amylase was not maximally repressed, showing that the regulation of the hydrolases may be partly reciprocal and partly independent.
TL;DR: Since some enzymes showed a high level of activity, A. pullulans could possibly be considered a promising source of extracellular lytic enzymes.
Abstract: One hundred and ninety-eight strains of Aureobasidium pullulans were screened for their ability to release extracellular hydrolytic enzymes into the cutural medium. Most of the isolates produced, to a varying extent, enzymes such as amylase, lipase (with different fats as substrates), protease (as caseinolysis and gelatin liquefaction), nucleases (ribonuclease and deoxyribonuclease), urease, and phosphatase. Neither cellulase nor chitinase were produced. Since some enzymes showed a high level of activity, A. pullulans could possibly be considered a promising source of extracellular lytic enzymes.
Journal Article•
TL;DR: A zymogen granule fraction has been isolated from rat pancreas, and its purity has been assessed by biochemical and morphological criteria and confirmed the absence of mitochondria, lysosomes, and rough endoplasmic reticulum fragments.
TL;DR: Using dispersed acini prepared from guinea pig pancreas, it is found that the structural requirements for cholecystokinin-induced stimulation of amylase secretion are the same as those for CholecyStokinIn-induced desensitization of amelase secretion.
Abstract: Using dispersed acini prepared from guinea pig pancreas, we found that the structural requirements for cholecystokinin-induced stimulation of amylase secretion are the same as those for cholecystokinin-induced desensitization of amylase secretion. 1) The relative potencies with which various C-terminal fragments of cholecystokinin cause stimulation are the same as their relative potencies for causing desensitization. 2) With each fragment tested, desensitization occurs with peptide concentrations that are supramaximal for causing stimulation of amylase secretion. 3) Fragments of cholecystokinin less efficacious in causing supramaximal inhibition of amylase secretion are also less efficacious in causing desensitization of amylase secretion. In contrast, there is no obvious fixed relation between the ability of a cholecystokinin fragment to cause stimulation of enzyme secretion and its ability to cause residual stimulation of enzyme secretion. Cholecystokinin and its C-terminal hexadecapeptide are 25-40% more efficacious than the C-terminal decapeptide, octapeptide, and heptapeptide in causing residual stimulation, and the C-terminal pentapeptide and tetrapeptide caused no detectable residual stimulation. The C-terminal tetrapeptide, however, can prevent as well as reverse the residual stimulation caused by other cholecystokinin fragments, and the ability of the tetrapeptide to prevent cholecystokinin-induced residual stimulation is itself fully reversible.
TL;DR: There is considerable human milk amylase activity in duodenal juice after a meal of human milk, which could contribute to the breast-fed infant's ability to digest starch.
Abstract: Amylase activity and isoenzyme pattern were determined in human milk from various stages of lactation and were compared with that in duodenal juice. The activity is high in colostrum and somewhat lower in milk from day 15 to day 90 after delivery. In this period of lactation, human milk contains higher amounts of amylase than duodenal juice from infants aged 1 to 6 months. Low activity was found in milk from 90 days or more after delivery. The amylase is of the salivary type. A pH of 5.3 does not inactivate the amylase; there is considerable human milk amylase activity in duodenal juice after a meal of human milk. Human milk amylase could thus contribute to the breast-fed infant's ability to digest starch.
TL;DR: It was showed that feeding rats a standard stock diet, but in liquid form to eliminate mastication, results in a reduction in the protein concentration of parotid saliva, a loss of several secretory proteins and nonparallel changes in some of the proteins which remain.
Abstract: The object of the present study was to determine of the secretory proteins of rats parotid saliva were altered following parotid gland atrophy induced by feeding rats a liquid stock diet which eliminated mastication. Compared to rats fed the pelleted stock diet, the parotid glands of rats fed liquid stock diet showed 40% to 55% reductions in gland weight and content of RNA, amylase, and protein. Gland DNA content was reduced by 26%. The concentration of protein and the activities of three secretory enzymes in parotid saliva were reduced by 40% to 70%. The secretory enzymes were affected in a nonparallel manner so that per milligram of secretory protein DNase was increased, while RNase and amylase were reduced. Examination of the protein composition by acrylamide gel electrophoresis showed that several secretory proteins were no longer present. This study showed that feeding rats a standard stock diet, but in liquid form to eliminate mastication, results in a reduction in the protein concentration of parotid saliva, a loss of several secretory proteins and nonparallel changes in some of the proteins which remain.
Journal Article•
TL;DR: It was concluded that high serum lipase activity is an unreliable basis for diagnosis of pancreatitis in dogs treated with dexamethasone.
Abstract: The effects of dexamethasone on the pancreas and on pancreatic amylase and lipase activities were determined in clinically normal dogs and in dogs with neurologic disease. Dexamethasone increased serum lipase activity without any histologic damage to the pancreas in either group of dogs. It decreased serum amylase activity in the normal dogs and had a variable effect in dogs with neurologic disease, with or without confirmed pancreatitis. It was suggested that high serum lipase activity in dexamethasone-treated dogs may not be attributable to pancreatitis and that the reasons are still unknown. It was concluded that high serum lipase activity is an unreliable basis for diagnosis of pancreatitis in dogs treated with dexamethasone. The data allowed no conclusion about an additive effect of dexamethasone and neurologic disease causing pancreatitis.