Isolation and activity of an alpha-amylase inhibitor from white kidney beans.
An alpha-amylase inhibitor (alpha-AI) was isolated from white kidney beans (Phaseolus vulgaris L) by ethanol fractional precipitation, ion exchange chromatography and gel filtration column chromatography. It was a homogeneity glycoprotein demonstrated by SDS-PAGE and gel filtration on CL-6B. The glycoprotein contained 88.2% protein and was rich in aspartic acid, glutamic acid, leucine, threonine and serine. The carbohydrate moiety was 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 beta-elimination reaction. The continuous oral administration of the alpha-AI (150 mg x kg(-1) x d(-1)) for 7 days can lower fasting blood glucose and 300 mg x kg(-1) x d(-1) alpha-AI for 7 days can improve the sugar tolerance on alloxan-dependent diabetic model rats. The result showed the alpha-AI obtained from white kidney beans had good hypoglycemic effect on alloxan induced diabetic rats and may have high potential pharmaceutical value as a regulative digestive-starch degradation in patients suffering from diabetes.
Zhang
Xiao-qi
XQ
Shaanxi Microbiology Institute, Xi' an 710043, China. zhangxq282@163.com
Yang
Ming-yan
MY
Ma
Yu
Y
Tian
Jia
J
Song
Ji-Rong
JR
D000496:Alloxan; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000139:chemically induced; D005260:Female; D006023:Glycoproteins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D008970:Molecular Weight; D009005:Monosaccharides / Q000032:analysis; D027805:Phaseolus / Q000737:chemistry; D037121:Plant Lectins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D014674:Plant Proteins, Dietary / Q000032:analysis; D010946:Plants, Medicinal / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D000516:alpha-Amylases / Q000037:antagonists & inhibitors*
D000596:Amino Acids; D001786:Blood Glucose; D006023:Glycoproteins; D009005:Monosaccharides; D037121:Plant Lectins; D014674:Plant Proteins, Dietary; C061510:alpha-amylase inhibitor, Phaseolus vulgaris; D000496:Alloxan; D000516:alpha-Amylases