Amylase inhibitor

Relatively thermostable proteins, which have an inhibitory effect on pancreatic amylase, are found in aqueous extracts of navy beans, wheat, and rye. As a result of the high thermostabilty, inhibitor activity is also detectable in breakfast cereals and bread. 

The amylase inhibitor of navy beans is instable in the stomach and becomes active only after preincubation with the enzyme in the absence of starch. As a result, it has no measurable influence on the digestion of starch by human beings. Moreover, the average amounts of inhibitor ingested with the food are small compared to the amylase activity present. 

Trypsin inhibitor Amount (mg/100 g diet) Inactivation (%) Body weight (g) Protein efficiency ratio (PER) 

In summary, it can be concluded that many foods in the raw state contain inhibitors of hydrolases. The heating processes normally used in the home and in industry generally inactivate the inhibitors more or less completely, so that damage to human health is not to be expected. As a result of the greatly varying thermal stability of the inhibitors, constant and careful control of raw materials and products is required, especially when new materials and processes are applied. 

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Carba-oligosaccharidic Alpha Amylase Inhibitors and Related Compounds. . 81... 

Carba-glycosylamines [2,3,4-trihydroxy-5-(hydroxymethyl)-1 -cyclohex-ylamine] and related compounds are well known to exist as components of the antibiotic validamycin complex and carba-oligosaccharidic alpha amylase inhibitors. ... 

Several mono-carba-oligosaccharidic alpha amylase inhibitors, such as acarbose and its homologs, amylostatins, trestatins, oligostatins, adipo-sins, and so on, have been isolated from cultures of micro-organisms, and considerable interest in the biochemistry and chemistry of this class of inhibitors has been stimulated. The characteristic core-structure for inhibitory action is composed of a trihydroxy(hydroxymethyl)cyclohexene moiety and a 4-amino-4,6-dideoxy-D-glucopyranose moiety, bonded by way of an imino linkage at the allylic position. A similar structural unit has been found in the antibiotic validamycins. 

In addition to proteases, other inhibitors reduce the activity of amylase and other digestive enzymes (Ishimoto et al, 1999). Many varieties of beans produce a glycoprotein that complexes with and inhibits a-amylase (Mirkov et al, 1995). The amylase inhibitors are non-competitive and thermostable (Gallaher and Schneeman, 1986) and, unlike protease inhibitors, do not elicit heightened secretion of amylase (Toskes, 1986). Although over-expression... 

ISHIMOTO M, YAMADA T, KAGA A (1999) Insecticidal activity of an alpha-amylase inhibitor-like protein resembling a putative precursor of alpha-amylase inhibitor in the common bean, Phaseolus vulgaris L. Biochim Biophys Acta. 1432 104-12. 

KOIKE D, YAMADERA K, DiMAGNO E p (1995) Effect of a wheat amylase inhibitor on canine carbohydrate digestion, gastrointestinal function, and pancreatic growth. Gastroenterology. 108 1221-9. 

LAYER P, RIZZA R A, ZINSMEISTER A R, CARLSON G L, DIMAGNO E P (1986) Effect of a purified amylase inhibitor on carbohydrate tolerance in normal subjects and patients with diabetes mellitus . Mayo Clin Proc. 61 442-7. 

MIRKOV T E, EVANS S V, WAHLSTROM J, GOMEZ L, YOUNG N M, CHRISPEELS M J (1995) Location of the active site of the bean alpha-amylase inhibitor and involvement of a Trp, Arg, Tyr triad. Glycobiology. 5 45-50. 

Expression of the insecticidal bean alpha-amylase inhibitor transgene has minimal detrimental effect on the nutritional value of peas fed to rats at 30% of the diet. JNutr. 129 1597-603. 

The magnitude of inhibition of polygalacturonase was found to be dependent on preincubation of inhibitor with the enzyme. Similar observations have been reported for other enzyme inhibitors (Shivaraj and Pattabiraman, 1980 Sharma and Pattabiraman, 1980 Padmanabhan and Shrasti, 1990). However, preincubation of the inhibitor with substrate did not show any effect on inhibitor activity. In contrast, Shivaraj and Pattabiraman (1980) and Buonocore et al. (1977), have observed inactivation of amylase inhibitor activity on pretreatment with starch. 

ALNXGQVDTXLAPXV Probable phospholipid transfer protein -oat (fragment) alpha-amylase inhibitor, Oat-B N-terminal /l-27/4ve a sotiva[73% 0.3... 

Structural aspects of proteinaceous cr -amylase inhibitor peptides 276... 

Several plant defensins have also been found to be inhibitors of various enzymes in plant pests. The plant defensins Slctl, SIo 2, and SIa3 were the first plant defensins where inhibition of a-amylase was shown at low concentration whereas purothionins inhibited a-amylase activity only at high concentrations. Blal and BIa2 isolated from barley are two more representatives of proteinaceous a-amylase inhibitors in the plant defensin family. ... 

There are also some peptides exhibiting a-amylase inhibitory potency. The plant defensins Slal, SIa2, and SIa3 from Sorghum bicolor and Blal and BIa2 from barley have been mentioned before. The knottin-type a-amylase inhibitor peptide AAI from Amaranthus hypochondtiacus is the smallest peptide ct-amylase inhibitor known to date. ... 

Structural aspects of proteinaceous a-amylase inhibitor peptides... 

S. Ueda, Y. Koba, and H. Chaen, Action of amylase inhibitors produced by Streptomyces sp. on some carbohydrate hydrolases and phosphorylases, Carbohydr. Res., 61 (1978) 253-264. 

Chemical Class a-Amylase inhibitor a-glucosidase inhibitor Clinical Pharmacology ... 

Preuss, H. G. (2009). Bean amylase inhibitor and other carbohydrate absorption blockers Effects on diabesity and general health. J. Am. Coll. Nutr. 28, 266-276. 

Su, Y. C., Chiu, R. J., Yu, N., Chang, W. R. (1984). The microbial production of amylase inhibitor and its application. I. Isolation and cultivation of Streptomyces nigrifaciens NTU-3314. Proceedings of the National Science Council, Republic of China. Part B, Life sciences, 8(4), 292-301. 

Other enzymes may be Inhibited, too. Llener (43) recently summarized the literature on amylase Inhibitors In wheat and their effectiveness against stored product pests ... 

Plausible mimics to the a-amylase inhibitor, tendamistat, found... 

The antagonism of GA action by ABA can be seen in studies of steady-state mRNA accumulation in aleurone cells, a major site of a-amylase synthesis in germinating cereal seeds (Fig. 3). GA treatment promotes the accumulation of high levels of a-amylase, shown by immunoprecipi-tation, while ABA, alone or with GA, completely represses this accumulation. In contrast, ABA clearly promotes the accumulation of a-amylase inhibitor mRNA, as determined by specific immunoprecipi-tation, while GA alone slightly reduces the level of a-amylase inhibitor mRNA. However, GA, together with ABA, does not decrease the level... 

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