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PURIFICATION AND PARTIAL CHARACTERIZATION OF A GLYCOPROTEIN ALPHA‐AMYLASE INHIBITOR FROM WHITE KIDNEY BEAN ( PHASEOLUS VULGARIS . L)
Author(s) -
YANG M.Y.,
ZHANG X.Q.,
MA Y.,
SHEN J.,
SONG J.R.,
ZHU H.L.
Publication year - 2008
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.2007.00147.x
Subject(s) - phaseolus , size exclusion chromatography , biochemistry , chemistry , amylase , chromatography , high performance liquid chromatography , biology , enzyme , botany
ABSTRACT A glycoprotein α‐amylase inhibitor (α‐AI) was extracted and purified from white kidney beans ( Phaseolus vulgaris. L) by ethanol fractional precipitation, ion exchange chromatography and gel filtration column chromatography. The homogeneity of α‐AI was demonstrated by gel filtration on sepharose CL‐6B and SDS‐polyacrylamide gel electrophoresis (SDS‐PAGE). The molecular weight was estimated to be about 36,000 Da by SDS‐PAGE. The glycoprotein α‐AI contained 88.2% protein and was rich in aspartic acid, glutamic acid, leucine, threonine and serine, with a trace amount of cysteine. The carbohydrate moiety, determined by reversed‐phase high‐performance liquid chromatography (RP‐HPLC), consisted of Man, Glc, Gal and Xyl in a mole ratio of 2.42:1.50:1.52:1.00. The glycan and the core protein backbone was connected by O‐linkage as determined by β‐elimination reaction.PRACTICAL APPLICATION The α‐amylase inhibitors are important because of their potential effects of insect control and crop plant defense against pests. The selective inhibition of human α‐amylase also plays an important role in reducing digestive‐starch degradation in patients suffering from diabetes and has high value in controlling human weight. In this paper, an α‐amylase inhibitor that effectively inhibits porcine pancreatic and salivary amylases was isolated and purified from white kidney bean. Therefore, it may have high potential pharmaceutical value as a regulative agent in reducing digestive‐starch degradation in patients suffering from diabetes and obesity.