Cellobiose-6-phosphate hydrolase (CelF) of Escherichia coli: characterization and assignment to the unusual family 4 of glycosylhydrolases.

ABSTRACT: The gene celF of the cryptic cel operon of Escherichia coli has been cloned, and the encoded 6-phospho-beta-glucosidase (cellobiose-6-phosphate [6P] hydrolase; CelF [EC 3.2.1.86]) has been expressed and purified in a catalytically active state. Among phospho-beta-glycosidases, CelF exhibits unique requirements for a divalent metal ion and NAD(+) for activity and, by sequence alignment, is assigned to family 4 of the glycosylhydrolase superfamily. CelF hydrolyzed a variety of P-beta-glucosides, including cellobiose-6P, salicin-6P, arbutin-6P, gentiobiose-6P, methyl-beta-glucoside-6P, and the chromogenic analog, p-nitrophenyl-beta-D-glucopyranoside-6P. In the absence of a metal ion and NAD(+), purified CelF was rapidly and irreversibly inactivated. The functional roles of the cofactors have

SUBMITTER: Thompson J 

PROVIDER: S-EPMC103698 | biostudies-literature | 1999 Dec

REPOSITORIES: biostudies-literature