Kohanski R A, Heinrikson R L
Department of Biochemistry, Mount Sinai School of Medicine, New York, New York 10029.
J Protein Chem. 1990 Aug;9(4):369-77. doi: 10.1007/BF01024612.
Rhodanese (thiosulfate: cyanide sulfurtransferase, EC 2.8.1.1.) was purified from chicken livers and its amino acid sequence was determined. The enzyme has a specific activity of 676 IU and a molecular weight of 32,255. The primary structure of 289 amino acids was solved by sequential Edman degradation of overlapping peptides obtained by selected enzymatic and chemical cleavages. The amino terminus was blocked, and the carboxy-terminus was heterogeneous. Comparison of the primary structure with bovine liver rhodanese showed 212 identically matched amino acids, and the majority of amino acid differences were conservative substitutions. Reaction of the enzyme with a 1.4-fold molar excess of [2-14C]iodoacetate led to inactivation of the enzyme and carboxymethylation of Cys-244; this modification was blocked by the substrate thiosulfate.
硫氰酸酶（硫代硫酸盐：氰化物硫转移酶，EC 2.8.1.1.）从鸡肝中纯化出来并测定了其氨基酸序列。该酶的比活性为676 IU，分子量为32255。通过对经选择的酶切和化学裂解获得的重叠肽段进行连续的埃德曼降解，解析出了由289个氨基酸组成的一级结构。氨基末端被封闭，羧基末端不均一。将该一级结构与牛肝硫氰酸酶进行比较，发现有212个氨基酸完全匹配，并且大多数氨基酸差异为保守性替换。该酶与1.4倍摩尔过量的[2-¹⁴C]碘乙酸反应导致酶失活以及半胱氨酸-244的羧甲基化；底物硫代硫酸盐可阻断这种修饰。
