Publications

• Identification, purification, and characterization of a D-arabinitol-specific dehydrogenase from Candida tropicalis.

  Quong M.W., Miyada C.G., Switchenko A.C., Goodman T.C.

  A novel D-arabinitol (DA) dehydrogenase was identified and purified more than 300-fold from Candida tropicalis. The enzyme is specific for DA and catalyzes the NAD(+)-dependent oxidation at carbon 4 to yield D-ribulose. Purification was accomplished by a combination of protamine sulfate and ammoni ... >> More

  A novel D-arabinitol (DA) dehydrogenase was identified and purified more than 300-fold from Candida tropicalis. The enzyme is specific for DA and catalyzes the NAD(+)-dependent oxidation at carbon 4 to yield D-ribulose. Purification was accomplished by a combination of protamine sulfate and ammonium sulfate precipitation and dye ligand chromatography on a reactive yellow 86 column. The apparent Km of the enzyme for DA ([NAD+] = 2.2 mM) is 39.8 mM. The apparent Km for NAD+ ([DA] = 384 mM) is 0.12 mM. The pH-optimum for the enzymatic oxidation of DA is approximately 10. Cofactor stereospecificity studies demonstrate that the enzyme catalyzes transfer of the 4(S) hydrogen of NADH with D-ribulose as substrate. The polyol substrate specificity of the present DA dehydrogenase makes the enzyme potentially useful for the development of a simple and specific method for the measurement of DA, a metabolite of pathogenic Candida spp. which has been described as a marker for disseminated candidiasis. << Less

  Biochem. Biophys. Res. Commun. 196:1323-1329(1993) [PubMed] [EuropePMC]

• A novel NADH-linked l-xylulose reductase in the l-arabinose catabolic pathway of yeast.

  Verho R., Putkonen M., Londesborough J., Penttila M., Richard P.

  An NADH-dependent l-xylulose reductase and the corresponding gene were identified from the yeast Ambrosiozyma monospora. The enzyme is part of the yeast pathway for l-arabinose catabolism. A fungal pathway for l-arabinose utilization has been described previously for molds. In this pathway l-arabi ... >> More

  An NADH-dependent l-xylulose reductase and the corresponding gene were identified from the yeast Ambrosiozyma monospora. The enzyme is part of the yeast pathway for l-arabinose catabolism. A fungal pathway for l-arabinose utilization has been described previously for molds. In this pathway l-arabinose is sequentially converted to l-arabinitol, l-xylulose, xylitol, and d-xylulose and enters the pentose phosphate pathway as d-xylulose 5-phosphate. In molds the reductions are NADPH-linked, and the oxidations are NAD(+)-linked. Here we show that in A. monospora the pathway is similar, i.e. it has the same two reduction and two oxidation reactions, but the reduction by l-xylulose reductase is not performed by a strictly NADPH-dependent enzyme as in molds but by a strictly NADH-dependent enzyme. The ALX1 gene encoding the NADH-dependent l-xylulose reductase is strongly expressed during growth on l-arabinose as shown by Northern analysis. The gene was functionally overexpressed in Saccharomyces cerevisiae and the purified His-tagged protein characterized. The reversible enzyme converts l-xylulose to xylitol. It also converts d-ribulose to d-arabinitol but has no activity with l-arabinitol or adonitol, i.e. it is specific for sugar alcohols where, in a Fischer projection, the hydroxyl group of the C-2 is in the l-configuration and the hydroxyl group of C-3 is in the d-configuration. It also has no activity with C-6 sugars or sugar alcohols. The K(m) values for l-xylulose and d-ribulose are 9.6 and 4.7 mm, respectively. To our knowledge this is the first report of an NADH-linked l-xylulose reductase. << Less

  J. Biol. Chem. 279:14746-14751(2004) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• D-arabitol metabolism in Candida albicans: studies of the biosynthetic pathway and the gene that encodes NAD-dependent D-arabitol dehydrogenase.

  Wong B., Murray J.S., Castellanos M., Croen K.D.

  Candida albicans produces large amounts of the pentitol D-arabitol in culture and in infected mammalian hosts, but the functional and pathogenic significance of D-arabitol in C. albicans is not known. In this study, we sought to elucidate the pathway by which C. albicans synthesizes D-arabitol and ... >> More

  Candida albicans produces large amounts of the pentitol D-arabitol in culture and in infected mammalian hosts, but the functional and pathogenic significance of D-arabitol in C. albicans is not known. In this study, we sought to elucidate the pathway by which C. albicans synthesizes D-arabitol and to identify and characterize key enzymes in this pathway. C. albicans B311 produced D-[14C-1]arabitol from [14C-2]glucose; this finding implies on structural grounds that D-ribulose-5-PO4 from the pentose pathway is the major metabolic precursor of D-arabitol. NAD- or NADP-dependent pentitol dehydrogenases catalyze the final steps in D-arabitol biosynthesis in other fungi; therefore, lysates of C. albicans B311 were tested for enzymes of this class and were found to contain a previously unknown NAD-dependent D-arabitol dehydrogenase (ArDH). The ArDH structural gene was cloned by constructing a new D-arabitol utilization pathway in Escherichia coli. The C. albicans ArDH gene expressed in E. coli and Saccharomyces cerevisiae an enzyme that catalyzes the reaction D-arabitol + NAD <-->D-ribulose + NADH; this gene was present as a single copy per haploid genome, and its deduced peptide sequence was homologous with sequences of several members of the short-chain dehydrogenase family of enzymes. These results suggest that (i) C. albicans synthesizes D-arabitol by dephosphorylating and reducing the pentose pathway intermediate D-ribulose-5-PO4 and (ii) ArDH catalyzes the final step in this pathway. << Less

  J. Bacteriol. 175:6314-6320(1993) [PubMed] [EuropePMC]