Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
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PMID:Effect dietary corn starch intake on pancreatic amylase and intestinal maltase and pH in cattle. 616 10

The mode of inhibition of a new complex oligosaccharide that inhibits the alpha-glucoside hydrolase activity of pancreatic and salivary alpha-amylase was studied. Kinetic analysis revealed a non-competitive type of inhibition with a Ki of 1.47 +/- 0.03 micrograms when tested against human pancreatic alpha-amylase and 3.89 +/- 0.08 micrograms against human salivary alpha-amylase. The inhibitory action of alpha-glucoside hydrolase inhibitor (alpha-GHI) on pancreatic amylase was observed over a wide range of pH (6.0--7.9), whereas the inhibition of salivary amylase was optimal at pH 6.5. Column chromatographic investigations suggested the possible formation of an enzyme-inhibitor complex because the mixture of alpha-GHI and pancreatic alpha-amylase was eluted as a single component through a Sephadex G200 column. However, this enzyme-inhibitor complex was easily separated into each component and the enzyme activity was fully recovered after electrophoresis.
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PMID:Effect of alpha-glucosidase inhibitor on human pancreatic and salivary alpha-amylase. 617 67

We tested a new amylase reagent involving chromogenic substrates (Pantrak, Calbiochem-Behring) for precision, dynamic range, and susceptibility to potential interferences. Two p-nitrophenyl-alpha-maltaosides are used as substrates, which amylase cleaves to shorter-chain p-nitrophenyl maltaosides, the latter then yielding p-nitrophenol from the activity of alpha-glucosidase. A series of 100 specimens were tested by Pantrak and two established methodologies. In both cases, correlation was excellent. Precision was good for all methods; CVs for Pantrak were 3.0 to 4.5%. The dynamic range of Pantrak extended to 800 U/L. Above-normal quantities of triglyceride, hemoglobin, or bilirubin did not cause spurious results, but anticoagulants that bind divalent cations should not be used. The Pantrak method has desirable analytical features and is easy to use.
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PMID:A new chromogenic amylase method compared with two established methods. 617 60

We evaluated the enzymic mechanism by which alpha-4-nitrophenyl maltoheptaoside serves as a substrate for serum amylase (EC 3.2.1.1). Because polymeric substrates possess many potential sites of cleavage, the expression of enzymic activity as the number of micromoles of substrate transformed under defined conditions by an enzyme must be changed to "one microequivalent of group transformed." Therefore, we measured the activity of the isoenzymes of alpha-amylase with regard to suitable oligosaccharide substrates, which allowed us to express the catalytic activity in IUB units (U). By "high-performance" liquid chromatography we investigated the mechanism of human pancreatic and salivary alpha-amylase action, both alone and in combination with alpha-glucosidase (EC 3.2.1.20). On the basis of these results, we can describe exactly the entire reaction sequence and determine the stoichiometric coefficient of 4-nitrophenol within 0.02 mol/L (SD) produced under the assay conditions.
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PMID:Mechanism of action of human pancreatic and salivary alpha-amylase on alpha-4-nitrophenyl maltoheptaoside substrate. 618 12

High performance liquid chromatography (HPLC) was used to monitor the purity of the substrates and to establish the patterns of hydrolysis of ortho- and para-nitrophenylmaltooligosaccharides (2-7 glucose residues) catalysed by human pancreatic and salivary alpha-amylase. Separation of the reaction products from the remaining substrate was performed on a TSK-G-2000 PW or a RP18 column. By measuring the quantitative distribution of products, and assuming a 5-subsite model for the active site of alpha-amylase, differential activities for the hydrolysis of the different glycosidic bonds in the 2 series of substrates were deduced. A highly sensitive coupled continuous assay system is based on the formation of phenyloligosaccharides with 1-4 glucose residues by the action of the amylase under test, coupled to hydrolysis of these products by yeast alpha-glucosidase. The most suitable test substrates were shown to be para-nitrophenyl-alpha-D-maltotetraoside and -pentaoside. Direct production of nitrophenol from ortho-nitrophenyl-alpha-D-maltotrioside is recommended for the measurement of the alpha-amylase activity of pancreatic and salivary gland secretions and extracts.
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PMID:Action pattern of human pancreatic and salivary alpha-amylase on 1,4-alpha-D-nitrophenylmaltooligosaccharides. 1,4-alpha-D-nitrophenylmaltooligosaccharides as substrates of alpha-amylse, I. 618 88

The major bovine serum isoamylases controlled by the AmI locus have been examined by gel filtration. On Sephadex G-200 the isoamylases can be resolved into two classes. The AmI A and AmI B have apparent molecular weights of 307,000 daltons whilst the AmI C isozyme has an apparent molecular weight of 44,400 daltons. The separation of the isozymes into two classes according to their elution behaviour on Sephadex G-200 has been shown to be an affinity separation. All three AmI isozymes are eluted from a non-dextran media (BioGel A1.5m) with apparent molecular weights of 417,000 daltons. The affinity separation on Sephadex G-200 has been shown to be inhibited by the addition of 1% (w/v) maltose to the elution buffer. In the presence of 1% (w/v) maltose all three AmI isozymes are coeluted from Sephadex G-200 with apparent molecular weights of 321,000 daltons. The maltase and amylase activities of the AmI isozymes were eluted coincidentally under all the conditions studied.
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PMID:Further studies on bovine serum amylase. 3. Affinity chromatography. 618 94

The action of certain substances known to induce cellular alterations, or encounted in the oral cavity, on the accumulation of 18F by Streptococcus mutans GS-5 has been investigated. A 62-67% inhibition in the number of 18F atoms bound per mg dry weight of cells could be induced by a 15 min pretreatment with 2.7 X 10(-4) M cetyltrimethylammoniumbromide, 1 X 10(-1) M acetic anhydride, or 7 X 10(-2) M HCl. Plate counts indicated that alteration of the cellular composition rather than viability was responsible for this diminution in 18F accumulation. Prior exposure for 15 min of this organism to 1 M HCHO or 0.1 M NaOH did not alter 18F accumulation. Of the common salts encountered in the oral cavity, CaCl2 enhanced 18F binding. Pretreatment of the assay cells for 15-160 min with 0.1-10 mg/ml of trypsin, pronase, protease, alpha-glucosidase, dextranase, or lactoferrin had no significant effect on the accumulation of 18F. However, pre-exposure of cells for 60 min to 1-10 mg/ml of either amylase or lipase induced a 40-67% inhibition in the binding of 18F, while lysozyme enhanced the binding of 18F by the cells. It would appear then that the binding of 18F by S. mutans may be altered by certain substances encountered in the oral cavity.
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PMID:The action of selected agents on the accumulation of 18F by Streptococcus mutans. 618 42

Pancreatic exocrine and endocrine secretory dynamics were studied in the isolated perfused pancreata of rats fed a normal diet or a diet supplemented with the alpha-glucosidase inhibitor, acarbose (150 mg/100 g food). After 10 days, the body weight of acarbose-treated rats was slightly lower than that of the control rats despite a larger food intake. Pancreatic amylase levels were significantly decreased, trypsinogen levels were significantly increased, and lipase levels were unaltered in the treated group compared with the controls. Basal and caerulein-stimulated flow rates of pancreatic juice as well as basal amylase output were similar in both groups, whereas caerulein-stimulated amylase output was significantly lower in the acarbose-treated group. Secretory responsiveness of amylase in the treated group was, however, about twice as high as that in the control group when related to pancreatic amylase content. Insulin release in response to either glucose or cerulein was similar in both groups. These findings indicate that treatment with acarbose may alter pancreatic enzyme content without changing the secretory responsiveness of either the exocrine or endocrine pancreas.
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PMID:Exocrine and endocrine pancreatic function in rats treated with alpha-glucosidase inhibitor (acarbose). 619 Nov 80

The effects of exposing laying hens and broilers daily to intermittent periods of 4 hr heating at 42 degrees C on the intestinal and pancreatic levels of amylase and maltase were investigated. The initial exposure to heat, characterized by heat stress, brought about a significant increase in the duodenum and jejunum parts of the tetra breed hen and only in the duodenum of broilers. The levels of amylase in the distal parts of the intestine of both breeds sharply decreased. The increase in amylase levels in the proximal parts of the intestine under the conditions of initial heating vanished after 3 days of heating; its levels continued to fall in the distal parts. In heat acclimatized laying hens the levels of amylase were lower than those of the control hens both in the intestine and pancreas. The pancreatic level of amylase was reversely related to the levels in the intestine. It is assumed that the intestinal level of amylase is regulated by the pancreas. These findings indicate that the pancreas plays an important role during the adaptation of chickens to heat, through the regulation of intestinal level of amylase. The response in maltase level to heat stress and heat acclimatization was insignificant.
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PMID:The effect of heat on the intestinal and pancreatic levels of amylase and maltase of laying hens and broilers. 619 24

Five Beagle dogs, equipped with duodenal and gastric fistulae, were fed a standard diet before receiving the same diet supplemented with wheat bran for 1 month. Pancreatic secretory investigations performed in conscious animals before and 1 month after bran administration showed a significant parallel increase in the flow rate of pancreatic secretion and the outputs of bicarbonate and amylase both in basal and secretin-stimulated conditions. The outputs of protein and chymotrypsin increased only in unstimulated secretions, while the output of lipase was strongly reduced in response to secretin. However, the small intestinal mucosa was not affected by bran administration. Dietary fiber did not alter the height of the villi or the activity of sucrase, maltase and aminopeptidase in mucosal homogenates or isolated brush border membranes from intestinal biopsies. These data suggest that wheat bran supplemented to the standard diet affects the exocrine pancreatic secretion but not intestinal enzyme activities involved in the absorption of carbohydrates and proteins in the dog.
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PMID:Effects of wheat bran on the exocrine pancreas and the small intestinal mucosa in the dog. 620 61


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