Alhomida A S
Department of Biochemistry, King Saud University, College of Science, Riyadh, Saudi Arabia.
Biochem Mol Biol Int. 1996 Aug;39(5):923-31. doi: 10.1080/15216549600201072.
The effect of certain sulfhydryl reagents and metal ions were studied on the carnitine acetyltransferase (CAT) activity from the skeletal muscle of the Arabian camel (Camelus dromedarius). DTNB and iodoacetamide caused concentration and time dependent inhibition of CAT activity. The inhibition seen with these sulfhydryl reagents could be protected with prior incubation of the enzyme with acetyl-Co A, suggesting that these reagents might interact with the same site. Among the various metal ions tested, Cu2+, Zn2+ and Hg2+ caused total inhibition at very low concentrations, while, Mn2+, Mo6+ and Co2+ caused between 32-52% inhibition at 10 mM concentrations. Alkali earth divalent metals Mg2+ and Ca2+ caused less than 15% inhibition at this concentration. These metal ions are probably interacting at certain nucleophilic groups in the enzyme thus disrupting its tertiary structure.
研究了某些巯基试剂和金属离子对阿拉伯骆驼（单峰驼）骨骼肌中肉碱乙酰转移酶（CAT）活性的影响。5,5'-二硫代双（2-硝基苯甲酸）（DTNB）和碘乙酰胺对CAT活性产生浓度和时间依赖性抑制。用乙酰辅酶A预先孵育酶可以保护这些巯基试剂所引起的抑制作用，这表明这些试剂可能与同一部位相互作用。在测试的各种金属离子中，Cu2+、Zn2+和Hg2+在非常低的浓度下就会导致完全抑制，而Mn2+、Mo6+和Co2+在10 mM浓度下会导致32%-52%的抑制。碱土二价金属Mg2+和Ca2+在此浓度下引起的抑制小于15%。这些金属离子可能在酶中的某些亲核基团处相互作用，从而破坏其三级结构。
