Asmus K D, Bensasson R V, Bernier J L, Houssin R, Land E J
Radiation Laboratory, University of Notre Dame, IN 46556, USA.
Biochem J. 1996 Apr 15;315 ( Pt 2)(Pt 2):625-9. doi: 10.1042/bj3150625.
Redox reactions of endogenous and exogenous sulphur-containing compounds are involved in protection against oxidative damage arising from the incidence and/or treatment of many diseases, including cancer. We have investigated, via pulse radiolysis, the one-electron oxidation of ergothioneine, a molecule with antioxidant properties which is detected at millimolar concentrations in certain tissues and fluids subject to oxidative stress, including erythrocytes and plasma. The spectrum of the transient species, assigned to the product of one-electron oxidation, observed after reaction of ergothioneine with the oxidizing radicals OH., N3. and CCl3O2. has a maximum absorption at 520 nm and is very similar to that obtained by oxidation of analogous molecules such as 2-mercaptoimidazole, 1-methyl-2-mercaptoimidazole, S-methyl- and S,N-dimethyl-ergothioneine. In the presence of vitamin C, the oxidized form of ergothioneine is repaired by a rapid reduction (k = 6.3 x 10(8) M(-1).s(-1)) producing ascorbyl radicals. This co-operative interaction between ergothionine and ascorbate, similar to that previously observed between vitamin E and ascorbate, may contribute to essential biological redox protection.
内源性和外源性含硫化合物的氧化还原反应参与了对包括癌症在内的许多疾病的发生和/或治疗所产生的氧化损伤的防护。我们通过脉冲辐解研究了麦角硫因的单电子氧化反应，麦角硫因是一种具有抗氧化特性的分子，在遭受氧化应激的某些组织和体液（包括红细胞和血浆）中能检测到毫摩尔浓度。麦角硫因与氧化自由基OH·、N3·和CCl3O2·反应后观察到的瞬态物种光谱，被归属于单电子氧化产物，其在520nm处有最大吸收，并且与通过氧化类似分子（如2-巯基咪唑、1-甲基-2-巯基咪唑、S-甲基-和S,N-二甲基-麦角硫因）所得到的光谱非常相似。在维生素C存在的情况下，麦角硫因的氧化形式通过快速还原（k = 6.3 x 10(8) M(-1)·s(-1)）得以修复，产生抗坏血酸自由基。麦角硫因和抗坏血酸盐之间的这种协同相互作用，类似于先前在维生素E和抗坏血酸盐之间观察到的相互作用，可能有助于重要的生物氧化还原防护。
