a Department of Pharmaceutical Sciences , Università degli Studi di Milano , Milan , Italy.
b Global Medical Information, Zambon S.p.A. , Bresso , Italy.
Free Radic Res. 2018 Jul;52(7):751-762. doi: 10.1080/10715762.2018.1468564. Epub 2018 May 9.
The main molecular mechanisms explaining the well-established antioxidant and reducing activity of N-acetylcysteine (NAC), the N-acetyl derivative of the natural amino acid l-cysteine, are summarised and critically reviewed. The antioxidant effect is due to the ability of NAC to act as a reduced glutathione (GSH) precursor; GSH is a well-known direct antioxidant and a substrate of several antioxidant enzymes. Moreover, in some conditions where a significant depletion of endogenous Cys and GSH occurs, NAC can act as a direct antioxidant for some oxidant species such as NO and HOX. The antioxidant activity of NAC could also be due to its effect in breaking thiolated proteins, thus releasing free thiols as well as reduced proteins, which in some cases, such as for mercaptoalbumin, have important direct antioxidant activity. As well as being involved in the antioxidant mechanism, the disulphide breaking activity of NAC also explains its mucolytic activity which is due to its effect in reducing heavily cross-linked mucus glycoproteins. Chemical features explaining the efficient disulphide breaking activity of NAC are also explained.
总结并批判性地回顾了 N-乙酰半胱氨酸（NAC）作为天然氨基酸 L-半胱氨酸的 N-乙酰衍生物所具有的明确抗氧化和还原活性的主要分子机制。抗氧化作用归因于 NAC 作为还原型谷胱甘肽（GSH）前体的能力；GSH 是一种众所周知的直接抗氧化剂，也是几种抗氧化酶的底物。此外，在某些情况下，内源性 Cys 和 GSH 大量消耗时，NAC 可以作为某些氧化剂如 NO 和 HOX 的直接抗氧化剂。NAC 的抗氧化活性还可能与其打破含硫蛋白的作用有关，从而释放游离巯基和还原蛋白，在某些情况下，如巯基白蛋白，具有重要的直接抗氧化活性。除了参与抗氧化机制外，NAC 的二硫键断裂活性还解释了其粘蛋白溶解活性，这归因于其降低高度交联粘蛋白糖蛋白的作用。还解释了解释 NAC 有效二硫键断裂活性的化学特征。
