CATABOLISM OF THYMIDINE IN HUMAN-BLOOD PLATELETS PURIFICATION AND PROPERTIES OF THYMIDINE PHOSPHORYLASE
CATABOLISM OF THYMIDINE IN HUMAN-BLOOD PLATELETS PURIFICATION AND PROPERTIES OF THYMIDINE PHOSPHORYLASE
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DOI：
10.1016/0005-2787(81)90174-x
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发表时间：
1981-01-01
期刊：
影响因子：
--
通讯作者：
BRICAUD, H
中科院分区：
文献类型：
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作者：
DESGRANGES, C;RAZAKA, G;BRICAUD, H
从人血小板中部分纯化了一种嘧啶核苷磷酸化酶。纯化的酶以及粗酶制剂催化胸苷和脱氧尿苷的磷酸解，但不催化尿苷的磷酸解，并且能够催化戊糖基从这些脱氧核糖核苷直接转移到尿嘧啶或胸苷;这种酶具有胸苷磷酸化酶的性质。它的分子量约为110，000，由2个相同的亚基组成;它是磷酸盐依赖性的，在pH值为5.7时具有最大活性，等电点为4.4。这种酶主要是细胞质来源的。尽管血小板胸苷磷酸化酶可以促进胸苷的降解或合成，但完整的血小板可以降解胸苷，但不能从胸苷合成胸苷。血小板对血浆胸苷的降解起重要作用。
A pyrimidine nucleoside phosphorylase was partially purified from human blood platelets. The purified enzyme, as well as crude enzyme preparations, catalyses the phosphorolysis of thymidine and deoxyuridine, but not of uridine, and is able to catalyse direct pentosyl transfer from these deoxyribonucleosides to uracil or thymine; this enzyme has the properties of a thymidine phosphorylase. It has a MW of about 110,000 and is composed of 2 identical subunits; it is phosphate dependent, has a maximal activity at a pH value of 5.7, and an isoelectric point of 4.4. This enzyme was mainly of cytoplasmic origin. Although platelet thymidine phosphorylase could promote the degradation or synthesis of thymidine, intact platelets degraded thymidine but were not able to synthesize thymidine from thymine. Blood platelets may play an important role in the degradation of plasma thymidine.