Hara A, Matsuura K, Tamada Y, Sato K, Miyabe Y, Deyashiki Y, Ishida N
Biochemistry Laboratory, Gifu Pharmaceutical University, Japan.
Biochem J. 1996 Jan 15;313 ( Pt 2)(Pt 2):373-6. doi: 10.1042/bj3130373.
We previously isolated three monomeric dihydrodiol dehydrogenases, DD1, DD2 and DD4, from human liver, and cloned a cDNA (C9) thought to encode DD2, which is identical with those for human bile-acid-binding protein and an oxidoreductase of human colon carcinoma HT29 cells. In the present study we have provided evidence that the C9 cDNA clone encodes DD1, not DD2. A recombinant enzyme expressed from the cDNA in a bacterial system was purified, and its catalytic properties, bile-acid-binding ability and primary sequence were compared with those of the hepatic dihydrodiol dehydrogenases. The results show that DD1 encoded by C9 possesses prostaglandin F synthase activity but low affinity for lithocholic acid, whereas DD2, showing differences of six amino acid residues from the DD1 sequence, exhibited high-affinity binding for the bile acid. Refined relationship between dihydrodiol dehydrogenases and their related proteins of human tissues is proposed.
我们之前从人肝脏中分离出三种单体二氢二醇脱氢酶,即DD1、DD2和DD4,并克隆了一个被认为编码DD2的cDNA(C9),它与人胆汁酸结合蛋白以及人结肠癌细胞HT29的一种氧化还原酶的cDNA相同。在本研究中,我们提供了证据表明C9 cDNA克隆编码的是DD1,而非DD2。从该cDNA在细菌系统中表达的重组酶被纯化,并将其催化特性、胆汁酸结合能力和一级序列与肝脏二氢二醇脱氢酶进行了比较。结果表明,由C9编码的DD1具有前列腺素F合酶活性,但对石胆酸的亲和力较低,而与DD1序列有六个氨基酸残基差异的DD2,对胆汁酸表现出高亲和力结合。本文提出了二氢二醇脱氢酶与其在人体组织中的相关蛋白之间更精确的关系。