Purification and partial characterization of malate dehydrogenase (decarboxylating) from Tritrichomonas foetus hydrogenosomes.
Malate dehydrogenase (decarboxylating) from Tritrichomonas foetus hydrogenosomes was purified close to homogeneity by a combination of differential centrifugation, zwitterionic detergent solubilization, Red-Sepharose chromatography and anion-exchange chromatography. The enzyme with apparent subunit size of 59 kDa and native molecular mass of 308 kDa utilized NAD+ preferentially to NADP+ as a cofactor and required Mn2+ or Mg2+ for its activity. Affinity curves for malate and coenzymes were hyperbolic. Km for malate was 100 microM and 458 microM in the presence of NAD+ and NADP+, respectively. Km for NAD+ and for NADP+ in the presence of malate was 18 microM and 207 microM, respectively. The enzyme is proposed to be a tetramer with a possible physiological role in the maintenance of an appropriate NAD+/NADH ratio in hydrogenosomes.
Hrdý
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I
Department of Parasitology, Charles University, Prague, Czech Republic.
Mertens
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E
D000818:Animals; D008291:Malate Dehydrogenase / Q000302:isolation & purification* / Q000378:metabolism*; D008293:Malates / Q000378:metabolism; D008345:Manganese / Q000378:metabolism; D008954:Models, Biological; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D015388:Organelles / Q000201:enzymology*; D016835:Tritrichomonas foetus / Q000201:enzymology*
D008293:Malates; D009243:NAD; D008345:Manganese; D009249:NADP; D008291:Malate Dehydrogenase; C030574:malate dehydrogenase (decarboxylating)