PURIFICATION AND PROPERTIES OF RIBONUCLEASES FROM HUMAN-URINE
PURIFICATION AND PROPERTIES OF RIBONUCLEASES FROM HUMAN-URINE
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DOI：
10.1016/0005-2744(80)90142-4
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发表时间：
1980-01-01
期刊：
影响因子：
--
通讯作者：
HIXSON, CV
中科院分区：
文献类型：
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作者：
CRANSTON, JW;PERINI, F;HIXSON, CV
正常人类尿液中存在的2种主要rnase （EC 3.1.27.5）已被高度纯化，并因其酶、物理、化学和结构特性而被广泛表征。其中一种酶，RNAase C，是一种糖蛋白，以RNA为底物时pH值为8.5，优先降解合成的均质聚合物poly(C)。这种酶通过柱电聚焦被分解成多个组分。先前用神经氨酸酶治疗导致单一形式的RNAase C具有10.4的等电点，表明电荷异质性是唾液酸含量变化的结果。RNAase C的HN2-和cooh末端序列分析表明，该酶与哺乳动物胰腺RNAase非常相似；数据显示一个由126个氨基酸残基组成的肽链和33%的碳水化合物含量。从尿液中分离出的第二种酶，称为RNAase U，也是一种糖蛋白，以RNA为底物时pH值为7.0，实际上对poly(C)无活性。RNAase U缺乏唾液酸，主要作为单一组分，具有高于pH 11.0的高碱性等电点。RNAase U的NH2-和COOH末端序列与胰腺RNAase的同源性不明显。该酶的氨基酸组成表明它与人脾RNAase非常相似。
The 2 major RNases (EC 3.1.27.5) present in normal human urine have been highly purified and extensively characterized for their enzymatic, physical, chemical and structural properties. One of the enzymes, RNAase C, is a glycoprotein which exhibits a pH optimum of 8.5 with RNA as the substrate and preferentially degrades the synthetic homoribopolymer poly(C). This enzyme is resolved into multiple components by column electrofocusing. Prior treatment with neuraminidase results in a single form of RNAase C with an isoelectric point of 10.4, indicating that the charge heterogeneity is the result of variability in sialic acid content. Amino acid composition of HN2- and COOH-terminal sequence analyses of RNAase C show that this enzyme is very similar to mammalian pancreatic RNAases; the data indicate a peptide chain of 126 amino acid residues and a 33% carbohydrate content. The 2nd enzyme isolated from urine, termed RNAase U, is also a glycoprotein which has a pH optimum of 7.0 with RNA as substrate and is virtually inactive against poly(C). RNAase U lacks sialic acid and focuses as a single component with a highly basic isoelectric point of greater than pH 11.0. The NH2- and COOH terminal sequences of RNAase U show little homology with the pancreatic RNAases. The amino acid composition of this enzyme indicates it is very similar to human spleen RNAase.