Fukuto J M, Stuehr D J, Feldman P L, Bova M P, Wong P
Department of Pharmacology, UCLA School of Medicine 90024.
J Med Chem. 1993 Sep 3;36(18):2666-70. doi: 10.1021/jm00070a010.
Arginine is oxidized by a class of enzymes called the nitric oxide synthases (NOS) to generate citrulline and, presumably, nitric oxide (.NO). N-Hydroxylation of a guanidinium nitrogen of arginine to generate N-hydroxyarginine (NOHA) has been shown to be a step in the biosynthesis of .NO. In an effort to elucidate the mechanism by which further oxidation of NOHA occurs, the oxidation of a model N-hydroxyguanidine compound by several peracids was studied in depth. This oxidative chemistry is a possible model for the enzymatic process since the corresponding urea (or citrulline equivalent product) is obtained along with an oxidized nitrogen species. The oxidized nitrogen product was, however, not .NO but rather HNO. .NO generation in this chemical system and in the enzymatic process would require another one-electron oxidation. The mechanistic details of this are further discussed.
精氨酸被一类称为一氧化氮合酶（NOS）的酶氧化，生成瓜氨酸以及推测的一氧化氮（·NO）。精氨酸胍基氮的N-羟基化生成N-羟基精氨酸（NOHA）已被证明是·NO生物合成中的一个步骤。为了阐明NOHA进一步氧化的机制，深入研究了几种过酸对模型N-羟基胍化合物的氧化。这种氧化化学是酶促过程的一种可能模型，因为会得到相应的尿素（或瓜氨酸等效产物）以及一种氧化态氮物种。然而，氧化态氮产物不是·NO，而是HNO。在这个化学体系和酶促过程中生成·NO需要另一个单电子氧化过程。对此的机理细节将进一步讨论。
