Cloning and expression analysis of a cDNA encoding an oxaloacetate acetylhydrolase from the brown-rot fungus Fomitopsis palustris

摘要

The brown-rot fungus Fomitopsis palustris possess two oxalate-producing enzymes: oxaloacetate acetylhydrolase (Fomitopsis palustris oxaloacetate acetylhydrolase, FpOAH), which catalyzes hydrolysis of oxaloacetate, and cytochrome c dependent glyoxylatedehydrogenase (Fomitopsis palustris glyoxylate dehydrogenase, FpGLOXDH), which catalyzes dehydrogenation of glyoxylate. Oxaloacetate was regarded as the predominant precursor for oxalate, because greater FpOAH activity was detected than FpGLOXDH activity. In this study, a 1080-bp cDNA encoding FpOAH was cloned. Recombinant FpOAH showed oxaloacetate acetylhydrolase (OAH, EC 3.7.1.1) activity, which confirmed that the isolated cDNA encoded FpOAH. Expression of the gene encoding FpOAH was 22.0-140.8 times greater than that encoding FpGLOXDH, depending on culture times. The gene expression results support our proposed idea that FpOAH plays more significant role than FpGLOXDH in oxalate biosynthesis in F. palustris.