Purification and characterization of NAD-dependent formate dehydrogenase from the white-rot fungus Ceriporiopsis subvermispora and a possible role of the enzyme in oxalate metabolism

Abstract: NAD-dependent formate dehydrogenase (FDH, EC 1.2.1.2.) was purified 34-fold with 5.8% yield as an electrophoretically homogeneous protein from the white-rot fungus Ceriporiopsis subvermispora. The native enzyme has a molecular mass of 84kDa consisting of two identical subunits as a homodimer. The K m values for formate and NAD were found to be 2.5mM and 28μM, respectively, at the optimum pH 6.5. The enzyme activity was inhibited by NADH, ADP, and ATP. The kinetic analysis indicated that the enzyme reaction proceeded by the ordered Bi Bi mechanism. Oxalate was found to be catabolized by mediations of oxalate decarboxylase (ODC, EC 4.1.1.2) and FDH during the vegetative growth of C. subvermispora, while it was oxidized by oxalate oxidase (OXO, EC 1.2.3.4) at the later stage of the cultivation. A possible role of the two-oxalate decomposing systems with ODC and OXO was discussed in relation to carbon metabolism of lignin-degrading basidiomycetes. [Copyright &y& Elsevier]