PURIFICATION AND PROPERTIES OF RECOMBINANT BETA-GALACTOSIDASE FROM BACILLUS-CIRCULANS

A gene encoding beta-galactosidase from Bacillus circulans which had h ydrolysis specificity for the beta 1-3 linkage was expressed in Escher ichia coli. The beta-galactosidase was purified from crude cell lysate s of E. coli by column chromatographies on Resource Q and Sephacryl S- 200 HR. The enzyme released galactose with high selectivity from oligo saccharides which had terminal beta 1-3 linked galactose residues. How ever it did not hydrolyse beta 1-4 linked galactooligosaccharides. Mor eover, Gal beta 1-3GlcNAc, Gal beta 1-3GalNAc, and their p-nitrophenyl glycosides were regioselectively synthesized in 10-46% yield by the t ransglycosylation reaction using this enzyme.