次黄嘌呤-鸟嘌呤磷酸核苷转移酶(Hypoxanthine-guanine phosphoribosyltransferase,简称HGPRT)为人体内一个翻译自HPRT1基因的酵素[1][2]
次黄嘌呤-鸟嘌呤磷酸核苷转移酶 | |||||||
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识别号 | |||||||
别名 | ;HPRTinosinic pyrophosphorylaseinosinate pyrophosphorylaseinosinic acid pyrophosphorylaseinosine 5'-phosphate pyrophosphorylaseIMP:diphosphate phospho-D-ribosyltransferaseHGPRTaseIMP diphosphorylaseIMP pyrophosphorylaseIMP-GMP pyrophosphorylase | ||||||
外部ID | GeneCards:[1] | ||||||
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物种 | 人类 | 小鼠 | |||||
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基因位置(UCSC) | 无数据 | 无数据 | |||||
PubMed查找 | 无数据 | 无数据 | |||||
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HGPRT为一种转移酶,可以催化将次黄嘌呤转换为肌苷酸(IMP),也可将鸟嘌呤的反应转为单磷酸鸟苷。这两个反应都是将PRPP的5-磷酸核苷转移至嘌呤上。HGPRT在核苷酸补救合成途径中扮演重要角色。
功能
HGPRT催化下列反应:
HGPRTase functions primarily to salvage purines from degraded DNA to reintroduce into purine synthetic pathways. In this role, it catalyzes the reaction between guanine and phosphoribosyl pyrophosphate (PRPP) to form GMP, or between hypoxanthine and phosphoribosyl pyrophosphate (PRPP) to form inosine monophosphate.
Substrates and inhibitors
Comparative homology modelling of this enzyme in L. donovani suggest that among all of the computationally screened compounds, pentamidine, 1,3-dinitroadamantane, acyclovir and analogs of acyclovir had higher binding affinities than the real substrate (guanosine monophosphate).[3]
疾病中的角色
此基因的突变往往导致高尿酸血症:
- 一些男性带有部分程度的HGPRT缺陷(约低于正常活动量20%)并因此导致血液中高浓度的尿酸。随之而来的是痛风以及肾结石。这症状称为凯利-塞米勒综合症。[4]
- 莱希-尼亨综合症起源由HPRT1突变导致的HGPRT缺陷。[5]
- 某些基因突变可能导致痛风。发病的风险与hypoxanthine-guanine phosphoribosyltransferase的缺陷程度成正比。
- HPRT expression on the mRNA and protein level is induced by hypoxia inducible factor 1 (HIF1A). HIF-1 is a transcription factor that directs an array of cellular responses that are used for adaptation during oxygen deprivation. This finding implies that HPRT is a critical pathway that helps preserve the cell's purine nucleotide resources under hypoxic conditions as found in pathology such as myocardial ischemia.[6]
The in silico and in-vitro correlation of these compounds were test in Leishmania HGPRT and validates the result.[7]
Hybridomas
Hybridomas are immortal (immune to cellular senescence), HGPRT+ cells that result from fusion of mortal, HGPRT+ plasma cells and immortal, HGPRT− myeloma cells. They are created to produce monoclonal antibodies in biotechnology. HAT medium inhibits de novo synthesis of nucleic acids, killing myeloma cells that cannot switch over to the salvage pathway, due to lack of HRPT1. The plasma cells in the culture eventually die from senesence, leaving pure hybridoma cells.
参见
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