Promising properties of a formate dehydrogenase from a methanol-assimilating yeast Ogataea parapolymorpha DL-1 in His-tagged form

The cDNA gene coding for formate dehydrogenase (FDH) from Ogataea parapolymorpha DL-1 was cloned and expressed in Escherichia coli. The recombinant enzyme was purified by nickel affinity chromatography and was characterized as a homodimer composed of two identical subunits with approximately 40 kDa in each monomer. The enzyme showed wide pH optimum of catalytic activity from pH 6.0 to 7.0. It had relatively high optimum temperature at 65 degrees C and retained 93, 88, 83, and 71 % of its initial activity after 4 h of exposure at 40, 50, 55, and 60 degrees C, respectively, suggesting that this enzyme had promising thermal stability. In addition, the enzyme was characterized to have significant tolerance ability to organic solvents such as dimethyl sulfoxide, n-butanol, and n-hexane. The Michaelis-Menten constant (K-m), turnover number (k(cat)), and catalytic efficiency (k(cat)/K-m) values of the enzyme for the substrate sodium formate were estimated to be 0.82 mM, 2.32 s(-1), and 2.83 mM(-1) s(-1), respectively. The K-m for NAD(+) was 83 mu M. Due to its wide pH optimum, promising thermostability, and high organic solvent tolerance, O. parapolymorpha FDH may be a good NADH regeneration catalyst candidate.