Yamada S, Tanaka Y, Furuichi M
Laboratory of Marine Biochemistry, Faculty of Fisheries, Kagoshima University, Japan.
Biochim Biophys Acta. 1995 Oct 19;1245(2):239-47. doi: 10.1016/0304-4165(95)00089-t.
High activity of histidine acetyltransferase (HISAT) was found in the brain and the lens of Nile tilapia Oreochromis niloticus. HISAT was semi-purified 4166-fold from the brain of Nile tilapia. The affinity chromatography using a Blue Sepharose 6 FF column was very effective for purification of this enzyme. The enzyme had a broad pH optimum from pH 7.0 to pH 9.5, and did not require any divalent metal ion. The semi-purified HISAT showed a strict substrate specificity for L-histidine (and its methyl derivatives) and acetylcoenzyme A (CoASAc). The reaction velocity fits normal Michaelis-Menten kinetics with respect to both L-histidine (Km, 0.45 mM) and CoASAc (Km, 0.027 mM). Gel filtration on Superdex 200 HR indicated the molecular weight of 39,000. It was presumed that the 38.5 kDa protein, which was intensely visualized in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was a single subunit derived from HISAT.
在尼罗罗非鱼（Oreochromis niloticus）的大脑和晶状体中发现了组氨酸乙酰转移酶（HISAT）的高活性。从尼罗罗非鱼的大脑中对HISAT进行了4166倍的半纯化。使用Blue Sepharose 6 FF柱的亲和层析对该酶的纯化非常有效。该酶的最适pH范围很宽，从pH 7.0到pH 9.5，并且不需要任何二价金属离子。半纯化的HISAT对L-组氨酸（及其甲基衍生物）和乙酰辅酶A（CoASAc）表现出严格的底物特异性。反应速度对L-组氨酸（Km，0.45 mM）和CoASAc（Km，0.027 mM）均符合正常的米氏动力学。在Superdex 200 HR上进行的凝胶过滤表明分子量为39,000。据推测，在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳中强烈显色的38.5 kDa蛋白质是源自HISAT的单个亚基。
