Syntheses of modified 2-chloro-4-nitrophenyl beta-maltopentaosides as useful substrates for assay of human alpha amylase.
Twenty-three novel 2-chloro-4-nitrophenyl beta-D-maltopentaosides modified at the 6(5) and/or 4(5) position were synthesized as substrates for human alpha amylase. Two human alpha amylases hydrolyzed 6(5)-deoxy-6(5)-, 6(5)-O-, and 4(5),6(5)-di-O-substituted derivatives at essentially a single D-glucosidic linkage, but 4(5),6(5)-O-bridged and 4(5)-O-substituted derivatives were hydrolyzed at two or more linkages. The amylases displayed smaller Km values for the compounds having hydrophobic modifications. In these derivatives, 2-chloro-4-nitrophenyl O-(6-bromo-6-deoxy-alpha-D-glucopyranosyl)-(1-->4)-tris[O-alpha-D- glucopyranosyl-(1-->4)]-beta-D-glucopyranoside (10), 2-chloro-4-nitrophenyl O-(6-azido-6-deoxy-alpha-D-glucopyranosyl)-(1-->4)- tris[O-alpha-D-glucopyranosyl-(1-->4)]-beta-D-glucopyranoside (19), and 2-chloro-4-nitrophenyl O-[6-O-(N-isopropyl)carbamoyl-alpha-D-glucopyranosyl]-(1-->4)- tris[O-alpha-D-glucopyranosyl-(1-->4)]-beta-D-glucopyranoside (30), which were rapidly hydrolyzed by the two amylases at a limited position at an approximately equal rate, were shown to be very useful blocked-type substrates for assay of human alpha amylase.
Tokutake
S
S
Research and Development Division, Kikkoman Corporation, Chiba, Japan.
Uchida
R
R
Kotani
K
K
Saito
K
K
Yamaji
N
N
D002240:Carbohydrate Sequence; D002863:Chromogenic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D006801:Humans; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry*; D013379:Substrate Specificity; D000516:alpha-Amylases / Q000032:analysis*
D002863:Chromogenic Compounds; D009844:Oligosaccharides; C049162:2-chloro-4-nitrophenyl-maltopentaoside; D000516:alpha-Amylases