Synthesis and use of isotope-labelled substrates for a mechanistic study on human α-methylacyl-CoA racemase 1A (AMACR; P504S)
作者:Daniel J. Darley、Danica S. Butler、Samuel J. Prideaux、Thomas W. Thornton、Abigail D. Wilson、Timothy J. Woodman、Michael D. Threadgill、Matthew D. Lloyd
DOI:10.1039/b815396e
日期:——
α-Methylacyl-CoA racemase (AMACR) is an important enzyme for the metabolism of branched-chain lipids and drugs. The enzyme is over-expressed in prostate and other cancers. AMACR 1A, the major splice variant, was purified from recombinant E. colicells as a His-tag protein. Purified enzyme catalysed chiral inversion of both S- and R-2-methyldecanoyl-CoA, with an equilibrium constant of 1.09 ± 0.14 (2S/2R). Reactions with 2H-labelled substrate showed that loss of the α-proton was a prerequisite for chiral inversion. Reactions conducted in 2H2O indicated that reprotonation was not stereospecific. These results are the first mechanistic study on any recombinant mammalian α-methylacyl-CoA racemase.
δ-甲基酰-CoA 消旋酶(AMACR)是支链脂质和药物代谢的一种重要酶。该酶在前列腺癌和其他癌症中过度表达。AMACR 1A 是主要的剪接变体,以 His 标记蛋白的形式从重组大肠杆菌中纯化。纯化的酶可催化 S- 和 R-2-methyldecanoyl-CoA 的手性反转,平衡常数为 1.09 ± 0.14 (2S/2R)。与 2H 标记底物的反应表明,δ-质子的损失是手性反转的先决条件。在 2H2O 中进行的反应表明,再质子化不是立体特异性的。这些结果是首次对任何重组哺乳动物δ-甲基酰-CoA 消旋酶进行机理研究。