Comparison of enzymatic characterization and gene organization of cyclic nucleotide phosphodiesterase 8 family in humans
Comparison of enzymatic characterization and gene organization of cyclic nucleotide phosphodiesterase 8 family in humans
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DOI：
10.1016/s0898-6568(02)00146-8
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发表时间：
2003-06-01
影响因子：
4.8
通讯作者：
Omori, K
中科院分区：
文献类型：
--
作者：
Gamanuma, M;Yuasa, K;Omori, K
克隆了人环核苷酸磷酸二酯酶8B(PDE8B)的全长cDNA。比较了编码885个氨基酸残基的显性变异体(PDE8B1)与PDE8A1的酶学特性。重组蛋白PDE8A1和PDE8B1在转染的COS细胞胞浆和胞膜部分均有表达。人PDE8B I为高亲和力cAMP-PDE，cAMP的K-m值为101+/-12 nM，大于PDE8A1的K-m值(40+/-1 nM)。PDE8A1的相对V-max为57+/-8%，而PDE8B1为100+/-12%。双嘧达莫对PDE8A1有中度抑制作用，IC50值为8+/-2um，但在较高浓度(IC50=23+/-2um)时可拮抗PDE8B I的活性。人PDE8B基因由22个外显子组成，全长217kb。虽然PDE8A1和PDE8B1之间的总序列同源性为68%，但PDE8A1和PDE8B1序列之间每个外显子的连接位置都很匹配，表明这两个基因在进化上是相似的。(C)2002 Elsevier Science Inc.保留所有权利。
Full-length cDNAs of human cyclic nucleotide phosphodiesterase 8B (PDE8B) were isolated. Enzymatic characteristics of a dominant variant encoding a protein of 885 residues (PDE8B1) were compared with those of PDE8A1. The recombinant PDE8A1 and PDE8B1 proteins of an entire form were produced in both cytosolic and membrane fractions of the transfected COS cells. The human PDE8B I was a high-affinity cAMP-PDE with K-m value of 101 +/- 12 nM for cAMP, which is greater than that of PDE8A1 (40 +/- 1 nM). Relative V-max value of PDE8A1 was 57 +/- 8% compared with that of PDE8B1 (100 +/- 12%). Although PDE8A1 was moderately inhibited by dipyridamole with IC50 value of 8 +/- 2 muM, the compound antagonized the PDE8B I activity at three-fold higher concentration (IC50 = 23 +/- 2 muM). The human PDE8B gene was composed of 22 exons, spanning over 217 kb. Although overall sequence identity between PDE8A1 and PDE8B1 was 68%, positions of junctions of each exon between the PDE8A1 and PDE8B1 sequences were well matched, indicating evolutionary relatedness of both genes. (C) 2002 Elsevier Science Inc. All rights reserved.