Substrate-like inhibition of the transgalactosylation reaction catalyzed by β-galactosidase from Aspergillus oryzae

摘要

The influence of key parameters in the kinetics of the transglycosylation system catalyzed by Aspergillus oryzae β-galactosidase when applied to the synthesis of galactosyl-ethylene glycol and galactosyl-glycerol has been studied. It was found that both acceptors were inhibitors of the enzyme, causing a decrease of 9 and 68 fold in enzyme catalytic efficiency in the presence of 4.0 M ethylene glycol and glycerol, respectively. The effect was characterized as "substrate-like inhibition", suggesting the formation of a nonproductive enzyme-acceptor complex. Inhibition constants for both acceptors were determined as 618 mM for ethylene glycol and 244 mM for glycerol.