摘要
核糖核酸酶抑制因子崔秀云（大连医科大学）核糖核酸酶抑制因子（Ｒｉｂｏｎｕｃｌｅａｓｅ Ｉｎ－ｈｉｂｉｔｏｒ，ＲＩ，ｏｒＲＮａｓｉｎ）是广泛存在于哺乳动物胞浆中的一种酸性蛋白质。分子量为５０ＫＤ。在正常细胞中，ＲＩ与ＲＮａｓｅＡ以１：１比例结合成复合物...
ibonuclease inhibitor (RI or RNasin) is a acidic cytoplasmic glycoprotein which molecular masswas estimated to be 50 kDa. RI inhibits the activities of ribonuclease A (RNase A) and angiogenin byforming a very tight complex.,RI has been purified and characterized from several mammalian tissues. Porcine RI contains 456residues which is built of 15 tandem homologous repeats of 29(A-type) and 28(B-type) amino acids.The RI contains 30 cysteine residues, all are in the free thiol form in the active inhibitor in the crystal.The three-dimensional structure of RI has s shape of horseshoe with overall dimensions 70 × 60 × 32A.The gene of placental ribonuclease inhibitor (RNH) is placed on the chromosome 11p15. 5. Molecular genetic alterations of chromosome 11p15. 5 are a common finding in human cancer. A cluster ofgenes was identified adjacent to this locus and one of these genes, HRCI was divergent by transcribed30 kb upstream from HRAS1. PFGE and southern analysis of genomic DNA suggested the order of thegenes: HRCI-HRASI-RNH.The definite biological function for RI remains unknown. Since its potency as an RNase inhibitorhas been widely demonstrated, it appears that RI might play a protective role against cytotoxic RNases.The relationship between RNase: RI ratio and the development of Alzheimer's disease has been described. Because RI strongly inhibitor angiogenin.It may be involved in the angiogenesis phenomenon. Solid tumor growth relays on the new formedblood vessels. RI might cut off the nutrient supply of tumor cells by inhibiting the formation of newblood Vessels.Our recently invesitigation showed that the exogenous placental ribonuclease inhibitor (PRI) caninhibit the tumor growth of loaded tumor mice. Our experiments also showed that the RI activity reduced in the blood of tumor patients and RI mRNA in the breast cancer cells was singnificantly lowerthan those of in the normal cells by RT-PCR and capillary electrophoresis.
出处
《生物工程进展》
CSCD
1996年第5期17-20,共4页
Progress in Biotechnology
关键词
核糖核酸酶
抑制因子
结构
病理
Ribonuclease inhibitor (RI, or RNasin) Ribenuclease (RNase) Angiogenin, Cancer, ageing.
