Preparation of Non-Reducing-End Substituted p-Nitrophenyl α-Maltopentaoside (FG5P) as a Substrate for a Coupled Enzymatic Assay for α-Amylases

Abstract

p-Nitrophenyl O-6-deoxy-6-[(2-pyridyl)amino]-α-D-glucopyranosyl-(1→4)-O-α-D-glucopyranosyl-(1→4)-O-α-D-glucopyranosyl-(1→4)-O-α-D-glucopyranosyl-(1→4)-α-D-glucopyranoside, FG5P, was prepared, taking advantage of the action of Bacillus macerans cyclodextrin glucanotransferase on a mixture of O-6-deoxy-6-[(2-pyridyl)amino]-α-D-glucopyranosyl-(1→4)-O-α-D-glucopyranosyl-(1→4)-O-α-D-glucopyranosyl-(1→4)-O-α-D-glucopyranosyl-(1→4)-O-α-D-glucopyranosyl-(1→4)-D-glucose and p-nitrophenyl α-glucoside. The maltopentaose derivative is resistant to α-glucosidase and is suitable as a substrate for the α-amylase assay coupled with α-glucosidase in which the activity of α-amylase is determined by measuring the amount of p-nitrophenol liberated by α-glucosidase from p-nitrophenyl α-glucoside and p-nitrophenyl α-maltoside produced by the action of α-amylase. This α-amylase assay method was applied for determination of α-amylases in human serum.