Department of Biochemistry, McGill University, 3655 Drummond Street, Montreal, PQ, H3G 1Y6 Canada.
Proc Natl Acad Sci U S A. 1985 Sep;82(18):6085-9. doi: 10.1073/pnas.82.18.6085.
Pulse-chase experiments with [(3)H]tetradecanoic acid and ATP showed that the bioluminescence-related 32-kDa acyltransferase from Vibrio harveyi can specifically catalyze the deacylation of a (3)H-labeled 18-kDa protein observed in extracts of this bacterium. The 18-kDa protein has been partially purified and its physical and chemical properties strongly indicate that it is fatty acyl-acyl carrier protein (acyl-ACP). Both this V. harveyi [(3)H]acylprotein and [(3)H]palmitoyl-ACP from Escherichia coli were substrates in vitro for either the V. harveyi 32-kDa acyltransferase or the analogous enzyme ("34K") from Photobacterium phosphoreum. TLC analysis indicated that the hexane-soluble product of the reaction is fatty acid. Phosphate ions and, to a lesser extent, organic alcohols stimulated the rate of acyl-protein cleavage. No significant cleavage of either E. coli or V. harveyi tetradecanoyl-ACP was observed in extracts of these bacteria unless the 32-kDa or 34K acyltransferase was present. Since these enzymes are believed to be responsible for the supply of fatty acids for reduction to form the aldehyde substrate of luciferase, the above results suggest that long-chain acyl-ACP is the source of fatty acids for bioluminescence.
脉冲追踪实验用 [(3)H]十四烷酸和 ATP 表明，发光相关的 32kDa 酰基转移酶可以特异性地催化 Vibrio harveyi 提取物中观察到的 18kDa 蛋白的去酰化。该 18kDa 蛋白已部分纯化，其物理和化学性质强烈表明它是脂肪酸酰基-酰基载体蛋白 (acyl-ACP)。V. harveyi [(3)H]酰基蛋白和大肠杆菌 [(3)H]棕榈酰-ACP 均可作为 V. harveyi 32kDa 酰基转移酶或 Photobacterium phosphoreum 中类似酶（“34K”）的体外底物。TLC 分析表明，反应的己烷可溶性产物是脂肪酸。磷酸离子和在较小程度上的有机醇刺激酰基蛋白裂解的速率。除非存在 32kDa 或 34K 酰基转移酶，否则在这些细菌的提取物中不会观察到大肠杆菌或 V. harveyi 十四烷酰-ACP 的明显裂解。由于这些酶被认为负责提供脂肪酸用于还原形成荧光素酶的醛底物，因此上述结果表明长链酰基-ACP 是生物发光的脂肪酸来源。
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