Naturally occurring α-amylase inhibitors: Structure/function relationships

Abstract

Perhaps because a-amylase is ubiquitous in all living systems, several natural inhibitors against this enzyme are found in biological materials. These inhibitors include the microbial nitrogen-containing carbohydrates with an oligobioamine unit, the microbial polypeptides such as Paim and Haim, and the larger protein inhibitors, found in cereals, legumes and some other higher plants. The protein inhibitors were discovered as early as 1933; however, much of the research has been performed since the mid 1970s, with important medical, nutritional and insect-control implications. The structures of several of the microbial N-containing carbohydrates and microbial polypeptides are known, and aminoacid sequences are also known for some of the higher plant protein inhibitors. Enzyme specificity studies with several a-amylases have been carried out, some detailed kinetic studies are available and a few chemical modification studies have been performed. Nevertheless, very little is known about why and how the compounds inhibit a-amylases, primarily those from animals and insects. R. Y. Yada et al. (eds.), Protein Structure-Function Relationships in Foods

THE MOLECULAR WEIGHT OF ?-AMYLASE INHIBITOR FROM WHITE BEAN cv 858B (PHASEOLUS VULGARIS L.) IS 56 kDa, NOT 20 kDa

“…SDS-PAGE results suggest that aAI-4 is composed of two types of subunits with different M,s of 12.4 and 17.2 kDa. Our SDS-PAGE results are consistent with reports that all the purified bean aAIs are composed of 2 or more subunits, based on PAGE and SDS-PAGE results (Ho et al 1994) . The M, of mature glycosylated active aAI-4 was shown to be 5 1 .O kDa based on gel filtration and PAGE results (Fig.…”

“…This provides evidence that the d I -4 molecules composition is a&. structue/fi.mction relationships have been reviewed in detail (Ho et al 1994). Bean aAIs reported so far contain carbohydrate and at least two or more subunits.…”

Plant toxic proteins with insecticidal properties. A review on their potentialities as bioinsecticides

“…In PPA the catalytic site has three conserved residues, Asp197, Glu233 and Asp300 (Bompard-Gilles et al, 1996) and five subsites for binding of the substrate glucan. The inhibition constant for the complex is very high and particularly in the case of aAI-1/PPA complex the inhibition constant is (10 210 -10 211 M) which suggested a large interface interaction between the two proteins (Ho et al, 1994). In fact, according to the structural analysis of the complexes, aAI-1/ PPA ( Fig.…”

α-Amylase Inhibition: Some Practical Considerations

“…Earlier reviews covered occurrence, chemical properties and reaction mechanisms of microbial and plant -amylase inhibitors [1][2][3]. The present review addresses the diverse group of -amylase inhibitors with focus on some aspects of their application in biotechnology for therapeutic treatment of diabetes as well as protection of crop plants from insects and phytopathogenic microorganisms, and production of transgenic plants with enhanced resistance to diseases.…”

“…The area of -amylase inhibitors has received increasing interest during the past 40 years and started even by a few reports dating back to 1933 [1,2]. Earlier reviews covered occurrence, chemical properties and reaction mechanisms of microbial and plant -amylase inhibitors [1][2][3].…”