A hyperactive NAD(P)H:Rubredoxin oxidoreductase from the hyperthermophilic archaeon Pyrococcus furiosus.
NAD(P)H:rubredoxin oxidoreductase (NROR) has been purified from the hyperthermophilic archaeon Pyrococcus furiosus. The enzyme is exceedingly active in catalyzing the NADPH-dependent reduction of rubredoxin, a small (5.3-kDa) iron-containing redox protein that had previously been purified from this organism. The apparent Vmax at 80 degrees C is 20,000 micromol/min/mg, which corresponds to a kcat/Km value of 300,000 mM(-1) s(-1). The apparent Km values measured at 80 degrees C and pH 8.0 for rubredoxin, NADPH, and NADH were 50, 5, and 34 microM, respectively. The enzyme did not reduce P. furiosus ferredoxin. NROR is a monomer with a molecular mass of 45 kDa and contains one flavin adenine dinucleotide molecule per mole but lacks metals and inorganic sulfide. The possible physiological role of this hyperactive enzyme is discussed.
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Department of Biochemistry and Molecular Biology and Center for Metalloenzyme Studies, University of Georgia, Athens, Georgia 30602, USA.
Adams
M W
MW
D000595:Amino Acid Sequence; D002384:Catalysis; D008969:Molecular Sequence Data; D009247:NADH, NADPH Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D020027:Pyrococcus furiosus / Q000201:enzymology*
C023091:rubredoxin-NAD+ reductase; D009247:NADH, NADPH Oxidoreductases