Development of new food materials using specific catalitical activities of microbial enzymes

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1.(1) gamma-Glutamyl-DOPA,gamma-glutamyl-Gln were synthesized using gamma-glutamyltrans-peptidase (GGT) from E.coli.(2) Mechanism of low temperature (20ﾟC) induction of E.coli GGT was studied. It was found to be regulated at transcriptional level.(3) X-ray crystallographical study of GGT was performed and three dimensional structure of the main chain was obtained.(4) Catabolism pathway of glutathione in E.coli cell was elucidated.2.(1)beta-Glucosidase gene was cloned from Bifidobacterium breve. It was overexpressed in E.coli and purified to electrophoretic homogeneity and crystallized.(2) This enzyme was found to catalyze the reverse reaction of hydrolysis reaction. This enzymatic activity was used to synthesize gentiobiose and fucosyl (beta1-6) glucose by serial columns of immobilized recombinant beta-glucosidase and activated charcoal. Various strains of Bifidobacteria, Lactobacillus and other intestinal bacteria were tested if they can catabolize thus synthesized fucosyl (beta1-6) glucose. We found that 8 out of 9 Bifidobacteria could cataboliza this disaccharide but no other bacteria could.(3) alpha-Galactosidase of Bifidobacterium was found to be an inducible enzyme. We isolated this enzyme and identified its characters. Its gene was cloned and the enzyme was overxpressed in E.coli.