来自牛肝脏的嘌呤核苷磷酸化酶。

Purine nucleoside phosphorylase from bovine liver.

Ikezawa Z, Nishino T, Murakami K, Tsushima K

Department of Biochemistry, Yokohama City University School of Medicine, Japan.

Comp Biochem Physiol B. 1978;60(2):111-6. doi: 10.1016/0305-0491(78)90113-x.

Abstract

Purine nucleoside phosphorylase (purine nucleoside:orthophosphate ribosyltransferase, E.C. 2.4.2.1) from liver of cattle, Bos taurus, was purified to homogeneity. Some properties of the enzymes from three different bovine tissues were compared and discussed. 2. The enzyme has a molecular weight of 83,000, a sedimentation coefficient of 5.3 S, a Stokes' radius of 3.71 nm, a frictional ratio of 1.30 and a subunit molecular weight of 30,000. 3. Optimal pH for xanthosine degradation is around 5.5, whereas a broad pH activity profile for inosine degradation was observed between 5.0 and 7.5. Lineweaver-Burk plots curved downward at high concentrations of substrates, inosine, phosphate and arsenate.

摘要

从黄牛（Bos taurus）肝脏中纯化出了嘌呤核苷磷酸化酶（嘌呤核苷：正磷酸核糖基转移酶，E.C. 2.4.2.1），使其达到了均一性。比较并讨论了来自三种不同牛组织的该酶的一些特性。2. 该酶的分子量为83,000，沉降系数为5.3 S，斯托克斯半径为3.71 nm，摩擦比为1.30，亚基分子量为30,000。3. 黄苷降解的最佳pH约为5.5，而肌苷降解在5.0至7.5之间呈现出较宽的pH活性曲线。在高浓度底物（肌苷、磷酸盐和砷酸盐）下，Lineweaver - Burk图向下弯曲。