Studies on Intra-cellular New Electron Transfer Systems Containing Aldehyde Oxidase as a Component.

黄嘌呤氧化酶、黄嘌呤脱氢酶、脂酰胺脱氢酶、nadph -细胞色素c还原酶和nadh -细胞色素b还原酶本身对n -氧化物和亚砜^5化合物都没有还原酶活性，即使有其电子供体存在。然而，当其中一种黄素酶及其电子供体与醛氧化酶结合时，两种情况下均观察到显著的n -氧化物和亚砜还原酶活性。这一事实表明，醛氧化酶能够与上述黄素酶偶联，形成新的电子传递系统，其中n -氧化物和亚砜化合物作为最终电子受体。兔活醛氧化酶被发现利用芳香羟肟酸、n -芳基脂肪羟肟酸和肟以及n -氧化物和亚砜化合物作为电子受体。此外，本研究还成功地从豚鼠肝脏和牛纤毛体中纯化了醛氧化酶。经十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS- PAGE）鉴定，纯化酶均相。凝胶过滤估计其分子量约为300,000，SDS-PAGE估计其分子量约为150,000。

Neither xanthine oxidase, xanthine dehydrogenase, lipoamide dehydrogenase, NADPH-cytochrome c reductase nor NADH-cytochrome b reductase by itself exhibited reductase activities towards N-oxide and sulfoxide ^5 compounds even in the presence of its electron donor. However, when one of these flavin enzymes and its electron donor were combined with aldehyde oxidase, significant N-oxide and sulfoxide reductase activities were observed in either case. This fact indicated that aldehyde oxidase is capable of coupling with such flavin enzymes as described above, forming new electron transfer systems in which N-oxide and sulfoxide compunds function as final electron acceptors.Rabbit live aldehyde oxidase has been found to utilize as electron acceptors aromatic hydroxamic acids, N-aryl aliphatic hydroxamic acids and oximes, as well as N-oxide and sulfoxide compounds. In the present study, furthermore, aldehyde oxidase was purified successfully from guinea pig liver and bovine ciliary body. In either case, the purified enzyme was homogeneous by the criterion of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS- PAGE). Its molecular weight was estimated to be about 300,000 by gel filtration and to be about 150,000 by SDS-PAGE.