title: Alpha-amylase assay with use of a benzyl derivative of p-nitrophenyl alpha-maltopentaoside, BG5P.
abstract: p-Nitrophenyl O-(6-O-benzyl)-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl- (1----4)-O-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl-(1-- --4)-alpha-D-glucopyranoside (BG5P) is hydrolyzed by both human salivary alpha-amylase (HSA) and human pancreatic alpha-amylase (HPA) to O-(6-O-benzyl)-alpha-D-glucopyranosyl-(1----4)-O-alpha-D-glucopyranosyl- (1----4)-alpha-D-glucopyranose (BG3) and p-nitrophenyl alpha-maltoside (G2P). Glucoamylase and alpha-glucosidase cannot hydrolyze BG5P because of the modification of the OH group of the 6-position of the non-reducing-end glucose residue with the benzyl group. Taking advantage of these characteristics of the substrate, BG5P, we developed a method to assay the total alpha-amylase activity in human fluids using glucoamylase and alpha-glucosidase as the coupled enzymes. This method is simple and can be used as the standard method for routine clinical assays of alpha-amylase activity.
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005087:Glucan 1,4-alpha-Glucosidase / Q000378:metabolism; D005936:Glucans / Q000378:metabolism*; D006027:Glycosides; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009596:Nitrophenols / Q000378:metabolism; D009844:Oligosaccharides; D010179:Pancreas / Q000201:enzymology; D012463:Saliva / Q000201:enzymology; D013053:Spectrophotometry; D013379:Substrate Specificity; D000516:alpha-Amylases / Q000097:blood / Q000378:metabolism*; D000520:alpha-Glucosidases / Q000378:metabolism
chemical_list: D005936:Glucans; D006027:Glycosides; D009596:Nitrophenols; D009844:Oligosaccharides; C056544:4-nitrophenyl-O-(6-O-benzyl)-glucopyranosyl(1--4)-O-glucopyranosyl(1--4)-O-glucopyranosyl(1--4)-O-glucopyranosyl(1--4)-glucopyranoside; D000516:alpha-Amylases; D000520:alpha-Glucosidases; D005087:Glucan 1,4-alpha-Glucosidase; C024836:4-nitrophenol