Two potent competitive inhibitors discriminating alpha-glucosidase family I from family II.
The inhibition kinetics for isoacarbose (a pseudotetrasaccharide, IsoAca) and acarviosine-glucose (pseudotrisaccharide, AcvGlc), both of which are derivatives of acarbose, were investigated with various types of alpha-glucosidases obtained from microorganisms, plants, and insects. IsoAca and AcvGlc, competitive inhibitors, allowed classification of alpha-glucosidases into two groups. Enzymes of the first group were strongly inhibited by AcvGlc and weakly by IsoAca, in which the K(i) values of AcvGlc (0.35-3.0 microM) were 21- to 440-fold smaller than those of IsoAca. However, the second group of enzymes showed similar K(i) values, ranging from 1.6 to 8.0 microM for both compounds. This classification for alpha-glucosidases is in total agreement with that based on the similarity of their amino acid sequences (family I and family II). This indicated that the alpha-glucosidase families I and II could be clearly distinguished based on their inhibition kinetic data for IsoAca and AcvGlc. The two groups of alpha-glucosidases seemed to recognize distinctively the extra reducing-terminal glucose unit in IsoAca.
Kimura
Atsuo
A
Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan. kimura@abs.agr.hokudai.ac.jp
Lee
Jin-Ha
JH
Lee
In-Su
IS
Lee
Hee-Seob
HS
Park
Kwan-Hwa
KH
Chiba
Seiya
S
Kim
Doman
D
D020909:Acarbose / Q000737:chemistry / Q000494:pharmacology*; D000606:Amino Sugars / Q000494:pharmacology*; D001667:Binding, Competitive; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002855:Chromatography, Thin Layer; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005947:Glucose / Q000737:chemistry; D007700:Kinetics; D008956:Models, Chemical; D009844:Oligosaccharides / Q000737:chemistry / Q000494:pharmacology*; D012275:Oryza / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D000520:alpha-Glucosidases / Q000737:chemistry* / Q000145:classification
D000606:Amino Sugars; D004791:Enzyme Inhibitors; D009844:Oligosaccharides; C493349:isoacarbose; C493350:acarviosine-glucose; C076099:acarviosine; D000520:alpha-Glucosidases; D005947:Glucose; D020909:Acarbose