METABOLISM OF PENTOSES AND PENTITOLS BY AEROBACTER AEROGENES. I. DEMONSTRATION OF PENTOSE ISOMERASE, PENTULOKINASE, AND PENTITOL DEHYDROGENASE ENZYME FAMILIES.

Mortlock, R. P. (Michigan State University, East Lansing) and W. A. Wood. Metabolism of pentoses and pentitols by Aerobacter aerogenes. I. Demonstration of pentose isomerase, pentulokinase, and pentitol dehydrogenase enzyme families. J. Bacteriol. 88:838-844. 1964.-Aerobacter aerogenes PRL-R3 is capable of utilizing as sole substrates for energy and growth seven of the eight aldopentoses and all of the four pentitols. Growth upon media containing either d-xylose, l-arabinose, d-ribose, d-arabitol, or ribitol occurred within 24 hr at 26 C. When d-arabinose or l-arabitol were used as growth substrates, growth was complete within 2 days; 4 days were required for growth on d-lyxose or xylitol, and 3 to 4 weeks for growth upon l-xylose. The versatility of this strain of A. aerogenes is due to an ability to synthesize in the presence of appropriate carbohydrates (inducers) families of enzymes which catalyze the metabolism of the carbohydrates (i.e., families of pentitol dehydrogenases, aldopentose isomerases, and pentulokinases). The specificity of induction for members of the enzyme families was found to vary, and cross induction of enzyme activity was common, especially among the pentitol dehydrogenases. Ribitol dehydrogenase activity was detected in extracts of cells grown on all of the above carbohydrates with the exception of d-xylose, l-arabinose, and d-ribose. The ribitol dehydrogenase activity of xylitol-grown cell extracts was fivefold higher than the activity in extracts of ribitol-grown cells.