Watanabe H, Narumi H, Inaba T, Ohgi K, Irie M
Department of Microbiology, Hoshi College of Pharmacy, Tokyo.
J Biochem. 1993 Dec;114(6):800-7. doi: 10.1093/oxfordjournals.jbchem.a124259.
A ribonuclease (RNase Oy) was purified to homogeneity on SDS-PAGE from the homogenate of oyster (Crussdstrea grigus). The apparent molecular weight estimated from SDS-PAGE was ca. 28 kDa. The pH optimum of the RNase was 5.0. The RNase released mononucleotides from RNA in the order of 3'-GMP, 3'-AMP, and 3'-UMP. The complete amino acid sequence of RNase Oy was determined, mostly by analyzing the peptides generated by BrCN cleavage or digestion by lysylendopeptidase, staphylococcal V8 protease, and alpha-chymotrypsin. The molecular weight of the protein moiety of RNase Oy deduced from the sequence was 24,359. The sequence of RNase Oy contained two typical histidine residues in segments common to the active site of RNase T2 family enzymes. The locations of six half cystine residues among eight were almost superimposable on those of four known plant RNases of RNase T2 family. The sequence homology between RNase Oy and five fungal and four plant RNases amount, to 43-56 amino acid residues. The amino acid sequence of the N-terminal part of RNase Oy is more similar to those of plant RNases than to those of fungal RNases. This RNase is the first RNase T2 family RNase from mollusc whose primary structure has been elucidated.
从牡蛎（Crussdstrea grigus）匀浆中通过十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳（SDS - PAGE）纯化出一种核糖核酸酶（RNase Oy），使其达到均一状态。从SDS - PAGE估计其表观分子量约为28 kDa。该核糖核酸酶的最适pH值为5.0。该核糖核酸酶从RNA释放单核苷酸的顺序为3'-鸟苷酸（3'-GMP）、3'-腺苷酸（3'-AMP）和3'-尿苷酸（3'-UMP）。主要通过分析由溴化氰（BrCN）裂解或赖氨酰内肽酶、葡萄球菌V8蛋白酶和α - 胰凝乳蛋白酶消化产生的肽段，确定了RNase Oy的完整氨基酸序列。从序列推导的RNase Oy蛋白质部分的分子量为24359。RNase Oy的序列在RNase T2家族酶活性位点的共同片段中包含两个典型的组氨酸残基。八个半胱氨酸残基中的六个位置与RNase T2家族的四种已知植物核糖核酸酶的位置几乎重叠。RNase Oy与五种真菌核糖核酸酶和四种植物核糖核酸酶之间的序列同源性为43 - 56个氨基酸残基。RNase Oy N端部分的氨基酸序列与植物核糖核酸酶的序列比与真菌核糖核酸酶的序列更相似。这种核糖核酸酶是第一个其一级结构已被阐明的来自软体动物的RNase T2家族核糖核酸酶。
