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pubmed:abstractText |
Not only sucrose but the five isomeric alpha-D-glucosyl-D-fructoses trehalulose, turanose, maltulose, leucrose, and palatinose are utilized by Klebsiella pneumoniae as energy sources for growth, thereby undergoing phosphorylation by a phosphoenolpyruvate-dependent phosphotransferase system uniformly at 0-6 of the glucosyl moiety. Similarly, maltose, isomaltose, and maltitol, 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 1H and 13C NMR spectroscopy. In cells of K. pneumoniae, hydrolysis of sucrose 6-phosphate is catalyzed by sucrose 6-phosphate hydrolase from Family 32 of the glycosylhydrolase superfamily. The five 6'-O-phosphorylated alpha-D-glucosyl-fructoses are hydrolyzed by an inducible (approximately 49-50 Kda) phospho-alpha-glucosidase from Family 4 of the glycosylhydrolase superfamily.
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pubmed:affiliation |
Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892-4350, USA. jthompson@dir.nidcr.nih.gov
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