Topic
Amylase
About: Amylase is a research topic. Over the lifetime, 14164 publications have been published within this topic receiving 296069 citations.
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TL;DR: It is indicated that persimmon leaf tea containing peculiar proanthocyanidins has a significant role in suppressing blood glucose elevation after starch intake, and that the best harvest time is June.
Abstract: The amounts and compositions of polyphenol in persimmon leaves and persimmon leaf tea were investigated. The predominant polyphenols in fresh leaves were water-soluble, and the contents reached a maximum (2.40% w/w) in June, and then gradually decreased. Separation of them followed by thiolytic degradation revealed that the major components were unique proanthocyanidin oligomers consisting of four heterogeneous extension units, including epigallocatechin-3-O-gallate. Persimmon leaf tea also contained similar proanthocyanidins with similar compositional units. Oral administration of starch with polyphenol concentrate of persimmon leaf tea resulted in a significant and dose-dependent decrease in the blood glucose level in Wistar rats. This effect is considered to be due to inhibition of pancreas α-amylase. These results indicate that persimmon leaf tea containing peculiar proanthocyanidins has a significant role in suppressing blood glucose elevation after starch intake, and that the best harvest time is June.
86 citations
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86 citations
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TL;DR: Shifts from a glucose- to a maltose-limited chemostat showed that maltose induces both the production and secretion of alpha-amylase, whereas at low glucose concentrations derepression resulted in an increased production rate.
Abstract: Summary: The intra- and extracellular concentrations of α-amylase in Aspergillus oryzae have been measured during batch culture of a wild-type strain and two recombinant strains. The mean intracellular level for the two recombinant strains was about four to five times the level of the wild-type strain. The recombinant strains also had a higher α-amylase productivity, whereas the residence time of the intracellular α-amylase pool was approximately the same for the three strains. At high glucose concentrations there was a low constitutive synthesis of α-amylase, whereas at low glucose concentrations derepression resulted in an increased production rate. Shifts from a glucose- to a maltose-limited chemostat showed that maltose induces both the production and secretion of α-amylase. Finally, from immunoblots, both a glycosylated and an unglycosylated α-amylase have been detected.
86 citations
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TL;DR: It is shown that insulin stimulates both growth and amylase synthesis of AR42J cells, a rat cell line that is derived from a transplantable tumor of the acinar pancreas, and that insulin induced a selective increase of amyl enzyme synthesis over general protein synthesis.
Abstract: Previous in vivo studies have suggested a long-term regulatory role for insulin in the exocrine pancreas. To directly study the long-term effects of insulin on the pancreas in vitro, we have used cultured AR42J cells, a rat cell line that is derived from a transplantable tumor of the acinar pancreas. Hormone-binding experiments with 125I-labeled hormones indicated that AR42J cells have insulin receptors, relatively fewer receptors for insulin-like growth factor II (IGF-II), and no detectable receptors for insulin-like growth factor I (IGF-I). Insulin at concentrations as low as 1 nM stimulated the growth of these cells, as measured by an increase in DNA and protein content, and in cell number. At 100 nM, where insulin had a maximal effect, the growth of AR42J cells was stimulated by 46.1 +/- 10.9% (mean +/- SEM, N = 11). Insulin increased the amylase activity of AR42J cells over the same concentration range that it stimulated growth; at 100 nM, insulin increased amylase by 91.0 +/- 15.4% (mean +/- SEM, N = 23). Immunoprecipitation of [35S]methionine-labeled proteins revealed that insulin induced a selective increase of amylase synthesis over general protein synthesis. These studies indicate, therefore, that insulin stimulates both growth and amylase synthesis of AR42J cells.
86 citations
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TL;DR: The changes in the ability of the refractory organic compounds to bind with enzyme proteins, combined with the analysis of the organic components by GC/MS, show that in the process of coking wastewater treatment no new toxic chemicals were produced.
85 citations