title: Biochemical and genetic characterization of a novel enzyme of pentitol metabolism: D-arabitol-phosphate dehydrogenase.
abstract: An enzyme with a specificity that has not been described previously, D-arabitol-phosphate dehydrogenase (APDH), has been purified from cell lysate of Enterococcus avium. SDS/PAGE indicated that the enzyme had a molecular mass of 41+/-2 kDa, whereas a molecular mass of 160+/-5 kDa was observed under non-denaturing conditions, implying that the APDH may exist as a tetramer with identical subunits. Purified APDH was found to have a narrow substrate specificity, converting only D-arabitol 1-phosphate and D-arabitol 5-phosphate into xylulose 5-phosphate and ribulose 5-phosphate, respectively, in the oxidative reaction. Both NAD(+) and NADP(+) were accepted as cofactors. Based on the partial protein sequences, the APDH gene was cloned. Homology comparisons place APDH within the medium-range dehydrogenase family. Unlike most members of this family, APDH requires Mn(2+) but no Zn(2+) for enzymic activity. The DNA sequence surrounding the gene suggests that it belongs to an operon that also contains several components of phosphotransferase system. Both biochemical evidence and protein sequence homology comparisons indicate that similar enzymes are widespread among the Gram-positive bacteria. Their apparent biological role is to participate in arabitol catabolism via the 'arabitol phosphate route', similar to the ribitol and xylitol catabolic routes described previously.
authors.affiliation: Danisco Cultor Innovation, Sokeritehtaantie 20, Kantvik 02460, Finland.
authors.forename: Mira
authors.initials: M
authors.lastname: Povelainen
authors.forename: Elena V
authors.initials: EV
authors.lastname: Eneyskaya
authors.forename: Anna A
authors.initials: AA
authors.lastname: Kulminskaya
authors.forename: Dina R
authors.initials: DR
authors.lastname: Ivanen
authors.forename: Nisse
authors.initials: N
authors.lastname: Kalkkinen
authors.forename: Kirill N
authors.initials: KN
authors.lastname: Neustroev
authors.forename: Andrei N
authors.initials: AN
authors.lastname: Miasnikov
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D001483:Base Sequence; D001671:Biochemistry / Q000379:methods; D016983:Enterococcus / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008670:Metals / Q000032:analysis / Q000378:metabolism; D008969:Molecular Sequence Data; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D010428:Pentosephosphates / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017421:Sequence Analysis; D013379:Substrate Specificity; D013401:Sugar Alcohol Dehydrogenases / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D013403:Sugar Phosphates / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D008670:Metals; D010428:Pentosephosphates; D011994:Recombinant Proteins; D013403:Sugar Phosphates; C474020:arabitol-5-phosphate; D009243:NAD; D009249:NADP; C031625:xylulose-5-phosphate; D013401:Sugar Alcohol Dehydrogenases