Hutson Susan M, Poole Leslie B, Coles Steven, Conway Myra E
Wake Forest University Health Sciences, Winston-Salem, NC, USA.
Methods Mol Biol. 2008;476:139-52. doi: 10.1007/978-1-59745-129-1_10.
The human branched chain aminotransferase enzymes are key regulators of glutamate metabolism in the brain and are among a growing number of redox-sensitive proteins. Studies that use thiol-specific reagents and electrospray ionization mass spectrometry demonstrate that the mitochondrial BCAT enzyme has a redox-active CXXC center, which on oxidation forms a disulfide bond (RSSR), via a cysteine sulfenic acid intermediate. Mechanistic details of this redox regulation were revealed by the use of mass spectrometry and dimedone modification. We discovered that the thiol group at position C315 of the CXXC motif acts a redox sensor, whereas the thiol group at position C318 permits reversible regulation by forming an intrasubunit disulphide bond. Because of their roles in redox regulation and catalysis, there is a growing interest in cysteine sulphenic acids. Therefore, development of chemical tags/methods to trap these transient intermediates is of immense importance.
人类支链氨基转移酶是大脑中谷氨酸代谢的关键调节因子，并且是越来越多的氧化还原敏感蛋白之一。使用硫醇特异性试剂和电喷雾电离质谱的研究表明，线粒体BCAT酶具有一个氧化还原活性的CXXC中心，该中心在氧化时通过半胱氨酸亚磺酸中间体形成二硫键（RSSR）。通过使用质谱和二甲基酮修饰揭示了这种氧化还原调节的机制细节。我们发现CXXC基序中C315位置的硫醇基团充当氧化还原传感器，而C318位置的硫醇基团通过形成亚基内二硫键允许可逆调节。由于它们在氧化还原调节和催化中的作用，对半胱氨酸亚磺酸的兴趣日益增加。因此，开发捕获这些瞬态中间体的化学标签/方法非常重要。
