Marshall, J. J.; Lauda, C. M.
JOURNAL NAME- J Biol Chem
VOL. 250
NO. 20
1975 Oct 25
PP. 8030-7
DOCUMENT TYPE- Journal Article
JOURNAL CODE- 2985121R
JOURNAL SUBSET- MEDJSIM
ISSN- 0021-9258
PUBLICATION COUNTRY- UNITED STATES
LANGUAGE- English NDN- 241-0024-8346-5

Kidney beans, Phaseolus vulgaris, contain a proteinaceous inhibitor of alpha-amylase, which we have named Bio-Phase 2250™. The inhibitor has been purified to homogeneity by conventional protein fractionation methods involving heat treatment, dialysis, and chromatography on DEAE-cellulose, Sephadex G-100, and CM-cellulose. Bio-Phase 2250™ is specific for animal alpha-amylases, having no activity towards the corresponding plant, bacterial, and fungal enzymes, or any other hydrolytic enzyme tested. Optimal inhibitory activity is expressed during preincubation of enzyme and inhibitor at pH 5.5 and 37 degrees. Substrate prevents inhibition. Measurement of the stoichiometry on inhibition showed that a 1:1 complex of alpha-amylase and inhibitor is formed. Complex formation was demonstrated by chromatography on Sephadex G-100. The Bio-Phase 2250™-amylase complex is dissociated at low pH values, apparently as a result of destruction of the enzyme; the complex cannot be dissociated by other conditions unfavorable for inhibition (low temperature or high pH). Bio-Phase 2250™ inhibits hog pancreatic alpha-amylase in a noncompetitive manner.