Phosphorylation and metabolism of sucrose and its five linkage-isomeric alpha-D-glucosyl-D-fructoses by Klebsiella pneumoniae

Not only sucrose but the five isomeric alpha -D-glucosyl-D-fructoses trehal ulose, turanose, maltulose, leucrose, and palatinose are utilized by Klebsi ella pneumoniae as energy sources for growth. thereby undergoing phosphoryl ation by a phosphoenolpyruvate-dependent phosphotransferase system uniforml y at O-6 of the glucosyl moiety. Similarly, maltose, isomaltose, and maltit ol, when exposed to these conditions, are phosphorylated regiospecifically at O-6 of their non-reducing glucose portion. The structures of these novel compounds have been established unequivocally by enzymatic analysis, acid hydrolysis, FAB negative-ion spectrometry, and H-1 and C-13 NMR spectroscop y. In cells of K. pneumoniae, hydrolysis of sucrose 6-phosphate is catalyze d by sucrose 6-phosphate hydrolase from Family 32 of the glycosylhydrolase superfamily. The five 6'-O-phosphorylated alpha -D-glucosyl-fructoses are h ydrolyzed by an inducible (similar to 49-50 Kda) phospho-alpha -glucosidase from Family 4 of the glycosylhydrolase superfamily. (C) 1001 Elsevier Scie nce Ltd. All rights reserved.