Regulatory Mechanism for Oxalate Production by the Enzymes and Its Related System in Wood-rotting Fungi.

草酸产生酶系统在木材腐烂真菌中的作用尚未阐明。大多数侵袭房屋木质部分的褐腐真菌都具有很强的产生草酸的活性，并且它们对铜木材防腐剂，包括CCA（铜，铬和砷酸盐）耐受，因为它们用产生的草酸盐来解毒铜，形成不溶性的草酸铜。结果得出以下结论：已知抑制木质素过氧化物酶单电子氧化的草酸也被发现抑制木质素模型片段与葡萄糖之间的非酚β - o - 4lcc模型化合物的裂解。从白腐菌中分离到草酸生成酶（乙醛酸氧化酶）、草酸脱羧酶和甲酸脱氢酶3种酶。本研究首次从木材腐烂真菌中无细胞提取到甲酸脱氢酶。从耐铜褐腐菌palustris中分离纯化了一种新的依赖细胞色素c的乙醛酸脱氢酶。光谱分析表明，该酶属于黄素血红蛋白家族。发现FMN是一个假基。因此，草酸盐的生产被发现是由细胞色素c的电子传递系统催化的，并且可能通过抑制电子传递系统来控制。

A role of oxalate producing enzyme systems in wood rotting fungi has not been elucidated. Most of brown rot fungi which attack wooden parts of houses have a strong activity to produce oxalic acid and they are tolerant to copper wood preservaties, including CCA (Copper, chrome and arsenate), because they detoxicate the copper with oxalate produced to form insoluble copper oxalate.As a result, following findings have been obtained.1.Oxalate which was known to inhibit the one elctron oxidation by lignin peroxidase was found also to inhibit the cleavage nonphenolic beta-O-4LCC model compound between lignin model moiety and glucose.2.Three enzymes, including oxalate producing enzyme (glyoxylate oxidase), oxalate decarboxylase, and formate dehydrogenase were isolated from a white-rot fungus Coriolus versicolor. Formate dehydrogenase was first cell-free extracted from wood rotting fungi by this investigation.3.We succeeded in isolating and purifying a new type of cytochrome c dependent glyoxylate dehydrogenase from copper tolerant brown rot fungus Tyromyces palustris. Spectral analysis of the enzyme showed that it belongs to a family of flavohemoproteins. FMN was found to be a prosthetic group. Thus, oxalate production was found to be catalyzed by the electron transport system with cytochrome c and may be controlled by inhibition of the electron transportation system.