内源性甲基精氨酸的病理学意义

内源性甲基精氨酸主要包括:N^G-单甲基-L-精氨酸(L-NMMA),非对称性二甲基精氨酸(ADMA)和对称性二甲基精氨酸(SDMA)。他们是胍基甲基化的精氨酸同类物,主要来自于体内甲基化蛋白的水解。其中非对称性甲基精氨酸和非对称性二甲基精氨酸对一氧化氮合酶(NOS)具有竞争性抑制作用,SDMA是ADMA的立体异构体,他对NOS没有作用。非对称性甲基精氨酸的代谢,转化和排泄过程受阻或生成过量都会造成这类物质在体内蓄积。ADMA水平的异常升高可使L-arg:NO通路受阻,导致一氧化氮(NO)合成减少,从而使与NO有关的生理、生化过程出现异常改变。各方面的研究显示,ADMA异常升高及其引发的NO合成障碍与心血管系统的某些疾病,如高血压、动脉粥样硬化、心衰等的发生与演变有密切的关系。

Endogenous methylarginine primarily include： NG monomethyl-L-arginine （L-NMMA）, Asymmetric dimethylarginine （ADMA） and symmetric dimethylarginine （SDMA）. They are both larginine＇ s congeners that guanido is methylated and both come from hydrolyzing of methylated protein. L-NMMA and ADMA have competitive inhibition to Nitric Oxide Synthose（NOS）. SDMA, the stereoisomer of ADMA, has no function to NOS. If metabolism, conversion and evacuation of ADMA are suffocated or producing too much ADMA,SDMA will be accumulated in vivo. The abnormally high level of ADMA block Larg：NO channel, result in NO reducing and abnormally change in some biochemical and physiology courses. Some researches suggest that abnormally high level of ADMA and synthesis trouble of NO accordingly have an intimate connection with cardiovascular disease, such as hypertension, atherosclerosis and heart failure.