Identification of a salvage pathway for D-arabinose in Mycobacterium smegmatis.
(1988) European journal of biochemistry / FEBS — Vol. 172, n° 1, p. 197-203 (1988)
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- Extracts of Mycobacterium smegmatis, which was adapted to growth in synthetic medium containing D-arabinose as sole carbon source, catalyzed the NADPH-mediated reduction of D-arabinose to D-arabitol. When arabinose-adapted bacteria were transferred to glycerol medium, resumption of growth was accompanied by a sharp drop in the specific activity of this enzyme. Moreover, extracts of cells grown in D-arabinose medium contained large amounts of an NAD+-linked pentitol dehydrogenase, as compared to bacteria multiplying in glycerol medium. The specific activity of mycobacterial extracts was ten-fold higher for D-arabitol than for its L-isomer, and eight-fold higher than for xylitol (it was more than forty-fold lower in the case of glycerol-grown cells). The product of the pentitol dehydrogenase reaction was identified as D-xylulose by three different procedures. On the basis of these data, it is suggested that utilization of exogenous D-arabinose in mycobacteria involves two dehydrogenases that catalyze the reactions D-arabinose NADPH----D-arabitol NAD+----D-xylulose, by virtue of which an aldopentose is converted into a ketopentose. The alditol: NADP oxidoreductase was isolated from homogenates of D-arabinose-adapted mycobacteria, and purified by DEAE-cellulose chromatography. The enzymatic activity was restricted to a single band which, under denaturing conditions, comigrated with albumin (approximately 46 kDa). It was insensitive to 2-mercaptoethanol, EDTA and NaF, and was inactivated at 70 degrees C.
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Wojtkiewicz, B., Szmidzinski, R., Jezierska, A., & Cocito, C. (1988). Identification of a salvage pathway for D-arabinose in Mycobacterium smegmatis. European journal of biochemistry / FEBS, 172(1), 197-203. https://doi.org/10.1111/j.1432-1033.1988.tb13873.x (Original work published 1988)