Department of Medicinal Chemistry & Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60612, USA.
Free Radic Biol Med. 2011 Oct 15;51(8):1558-66. doi: 10.1016/j.freeradbiomed.2011.06.030. Epub 2011 Jul 5.
It is well established that nitric oxide ((•)NO) reacts with cellular iron and thiols to form dinitrosyliron complexes (DNIC). Little is known, however, regarding their formation and biological fate. Our quantitative measurements reveal that cellular concentrations of DNIC are proportionally the largest of all (•)NO-derived adducts (900 pmol/mg protein, or 45-90 μM). Using murine macrophages (RAW 264.7), we measured the amounts, and kinetics, of DNIC assembly and disappearance from endogenous and exogenous sources of (•)NO in relation to iron and O(2) concentration. Amounts of DNIC were equal to or greater than measured amounts of chelatable iron and depended on the dose and duration of (•)NO exposure. DNIC formation paralleled the upregulation of iNOS and occurred at low physiologic (•)NO concentrations (50-500 nM). Decreasing the O(2) concentration reduced the rate of enzymatic (•)NO synthesis without affecting the amount of DNIC formed. Temporal measurements revealed that DNIC disappeared in an oxygen-independent manner (t(1/2)=80 min) and remained detectable long after the (•)NO source was removed (>24 h). These results demonstrate that DNIC will be formed under all cellular settings of (•)NO production and that the contribution of DNIC to the multitude of observed effects of (•)NO must always be considered.
众所周知，一氧化氮（(•)NO）与细胞内的铁和硫醇反应，形成二硝酰基铁复合物（DNIC）。然而，关于它们的形成和生物学命运，我们知之甚少。我们的定量测量表明，DNIC 的细胞浓度是所有（•）NO 衍生加合物中最大的（900 pmol/mg 蛋白，或 45-90 μM）。使用小鼠巨噬细胞（RAW 264.7），我们测量了内源性和外源性（•）NO 来源中 DNIC 的组装和消失的量和动力学，以及铁和 O2 浓度的关系。DNIC 的量等于或大于可螯合铁的量，并且取决于（•）NO 暴露的剂量和持续时间。DNIC 的形成与 iNOS 的上调平行发生，并且发生在低生理（•）NO 浓度（50-500 nM）下。降低 O2 浓度会降低酶促（•）NO 合成的速率，而不影响形成的 DNIC 的量。时间测量表明，DNIC 以非依赖于氧的方式消失（t1/2=80 分钟），并且在（•）NO 源去除后很长时间仍可检测到（>24 小时）。这些结果表明，DNIC 将在（•）NO 产生的所有细胞环境中形成，并且必须始终考虑 DNIC 对（•）NO 观察到的多种作用的贡献。
