Weickmann J L, Elson M, Glitz D G
Biochemistry. 1981 Mar 3;20(5):1272-8. doi: 10.1021/bi00508a035.
A ribonuclease (RNase) has been isolated from normal human pancreas obtained upon autopsy. About 5 mg of RNase is normally recovered per kilogram of pancreas, equivalent to ca. 70% of the total activity and a 700-fold purification from the initial acidified extract. The specific activity of the purified enzyme is identical with that of bovine pancreatic ribonuclease, and a single component is found in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, gel filtration, and reversed-phase high-pressure liquid chromatography. Aggregation of the protein is found upon ultracentrifugation under native and denaturing conditions, and several bands of equal specific activity are seen in polyacrylamide gel electrophoresis of the native protein. At least two components are glycoproteins. A molecular weight of 15 000 is estimated from sodium dodecyl sulfate gel electrophoresis, gel filtration, and amino acid and peptide analyses. The enzyme is related to bovine pancreatic RNase, but distinguishable by amino acid analysis, tryptic peptide maps, and low cross-reactivity of antibodies with the heterologous enzymes. The human enzyme is also inactivated by treatment with iodoacetic acid at pH 5.5 and is essentially identical with bovine RNase in its far-ultraviolet circular dichroism spectrum. The human RNase is like bovine pancreatic RNase catalytically; RNA is cleaved at pyrimidine residues, and activity against poly(cytidylic acid) is high.
已从尸检获得的正常人胰腺中分离出一种核糖核酸酶（RNase）。通常每千克胰腺可回收约5毫克RNase，相当于总活性的约70%，并且相对于初始酸化提取物有700倍的纯化。纯化酶的比活性与牛胰腺核糖核酸酶相同，在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、凝胶过滤和反相高压液相色谱中均发现单一成分。在天然和变性条件下超速离心时发现蛋白质聚集，天然蛋白质的聚丙烯酰胺凝胶电泳中可见几条比活性相同的条带。至少有两种成分是糖蛋白。根据十二烷基硫酸钠凝胶电泳、凝胶过滤以及氨基酸和肽分析估计分子量为15000。该酶与牛胰腺RNase相关，但通过氨基酸分析、胰蛋白酶肽图谱以及抗体与异源酶的低交叉反应性可区分。人源酶在pH 5.5下用碘乙酸处理会失活，并且其远紫外圆二色光谱与牛RNase基本相同。人源RNase在催化方面与牛胰腺RNase相似；RNA在嘧啶残基处被切割，对聚（胞苷酸）的活性很高。
