The putative malate/lactate dehydrogenase from Pseudomonas putida is an NADPH-dependent delta1-piperideine-2-carboxylate/delta1-pyrroline-2-carboxylate reductase involved in the catabolism of D-lysine and D-proline.
A Pseudomonas putida ATCC12633 gene, dpkA, encoding a putative protein annotated as malate/L-lactate dehydrogenase in various sequence data bases was disrupted by homologous recombination. The resultant dpkA(-) mutant was deprived of the ability to use D-lysine and also D-proline as a sole carbon source. The dpkA gene was cloned and overexpressed in Escherichia coli, and the gene product was characterized. The enzyme showed neither malate dehydrogenase nor lactate dehydrogenase activity but catalyzed the NADPH-dependent reduction of such cyclic imines as Delta(1)-piperideine-2-carboxylate and Delta(1)-pyrroline-2-carboxylate to form L-pipecolate and L-proline, respectively. NADH also served as a hydrogen donor for both substrates, although the reaction rates were less than 1% of those with NADPH. The reverse reactions were also catalyzed by the enzyme but at much lower rates. Thus, the enzyme has dual metabolic functions, and we named the enzyme Delta(1)-piperideine-2-carboxylate/Delta(1)-pyrroline-2-carboxylate reductase, the first member of a novel subclass in a large family of NAD(P)-dependent oxidoreductases.
Muramatsu
Hisashi
H
Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
Mihara
Hisaaki
H
Kakutani
Ryo
R
Yasuda
Mari
M
Ueda
Makoto
M
Kurihara
Tatsuo
T
Esaki
Nobuyoshi
N
D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003067:Coenzymes / Q000378:metabolism; D019143:Evolution, Molecular; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism*; D008291:Malate Dehydrogenase / Q000378:metabolism; D009249:NADP / Q000378:metabolism*; D010875:Pipecolic Acids / Q000378:metabolism*; D011392:Proline / Q000378:metabolism*; D016958:Pseudomonas putida / Q000201:enzymology* / Q000235:genetics; D011762:Pyrroline Carboxylate Reductases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D013696:Temperature
D001426:Bacterial Proteins; D003067:Coenzymes; D010875:Pipecolic Acids; C036512:delta(1)-piperidine-2-carboxylic acid; D009249:NADP; D011392:Proline; D007770:L-Lactate Dehydrogenase; D008291:Malate Dehydrogenase; D011762:Pyrroline Carboxylate Reductases; D008239:Lysine