Enzymatic synthesis of p-nitrophenyl alpha-maltoheptaoside by transglycosylation of maltohexaose-forming amylase.
An extracellular maltohexaose-forming amylase [EC 3.2.1.98] from Klebsiella pneumoniae mutant is a normal hydrolytic enzyme that hydrolyzes short-chain amylose (DP = 23) to give about 40% maltohexaose. Transglycosylation from maltoheptaose to the 4-position of p-nitrophenyl alpha-glucoside was efficiently induced through the use of maltohexaose-forming amylase in an aqueous methanol solution. The enzyme specifically produced p-nitrophenyl alpha-maltoheptaoside (13% of the p-nitrophenyl alpha-glucoside) from maltoheptaose as a donor and p-nitrophenyl alpha-glucoside as an acceptor. The yield of p-nitrophenyl alpha-maltoheptaoside depended on the concentration of methanol solvent, the pH, and temperature. Furthermore, the use of the aqueous methanol system in the reaction not only improved the solubility of p-nitrophenyl alpha-glucoside but also greatly increased the formation of p-nitrophenyl alpha-maltoheptaoside, which is a useful substrate for assay of human amylase in serum and urine.
Research Laboratory, Nihon Shokuhin Kako Co., Ltd., Shizuoka, Japan.
K
K
Ogawa
O
O
Uejima
T
T
Nakakuki
T
T
Usui
K
K
Kainuma
D002863:Chromogenic Compounds; D005960:Glucosides / Q000096:biosynthesis*; D006027:Glycosides / Q000096:biosynthesis*; D006031:Glycosylation; D007700:Kinetics; D007711:Klebsiella pneumoniae / Q000201:enzymology* / Q000235:genetics; D009154:Mutation; D013816:Thermodynamics; D000520:alpha-Glucosidases / Q000378:metabolism*
D002863:Chromogenic Compounds; D005960:Glucosides; D006027:Glycosides; C036167:4-nitrophenyl maltoheptaoside; D000520:alpha-Glucosidases; C065485:glucan 1,4-alpha-maltohexaosidase