NAD(+)-dependent isoform of 11 beta-hydroxysteroid dehydrogenase. Cloning and characterization of cDNA from sheep kidney.
NAD(+)-dependent isoform of 11 beta-hydroxysteroid dehydrogenase. Cloning and characterization of cDNA from sheep kidney.
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DOI：
10.1016/s0021-9258(18)47142-6
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发表时间：
1994-10
期刊：
影响因子：
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通讯作者：
A. K. Agarwal;T. Mune;T. Mune;C. Monder;P. White
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文献类型：
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作者：
A. K. Agarwal;T. Mune;T. Mune;C. Monder;P. White
11β-羟基类固醇脱氢酶 (11-HSD) 催化皮质醇转化为可的松，催化皮质酮转化为 11-脱氢皮质酮。可能需要这种活性才能赋予盐皮质激素受体正常的配体特异性。尽管之前从大鼠肝脏中分离出了 11-HSD 的同工酶，但盐皮质激素靶组织中明显表达了不同的同工酶。我们通过使用非洲爪蟾卵母细胞的表达筛选，分离出了编码该同工酶的绵羊肾 cDNA 克隆。该 cDNA 长度为 1.8 KB，编码 427 个氨基酸残基的蛋白质，预测 M(r) 为 46,700。当在卵母细胞中表达时，该酶作为 NAD(+) 依赖性 11 β-脱氢酶发挥作用，对类固醇具有非常高的亲和力，但没有可检测到的还原酶活性。它的氨基酸序列与 17 β-羟基类固醇脱氢酶的 NAD(+) 依赖性同工酶有 37% 相同，但与 11-HSD 的 NADP(+) 依赖性肝脏同工酶只有 20% 相同。它在肾脏和肾上腺中表达水平较高，在结肠中表达水平较低。相应的基因以单拷贝形式存在于绵羊基因组中。在人类中，该基因是明显盐皮质激素过多综合征的候选位点，盐皮质激素过量综合征是一种高血压，推测是由于盐皮质激素靶组织中 11-HSD 缺乏所致。
11 beta-Hydroxysteroid dehydrogenase (11-HSD) catalyzes the conversion of cortisol to cortisone and corticosterone to 11-dehydrocorticosterone. This activity may be required to confer normal ligand specificity upon the mineralocorticoid receptor. Although an isozyme of 11-HSD was previously isolated from rat liver, a different isozyme is apparently expressed in mineralocorticoid target tissues. We isolated a sheep kidney cDNA clone encoding this isozyme by expression screening using Xenopus oocytes. The cDNA is 1.8 kilobase pairs in length and encodes a protein of 427 amino acid residues with a predicted M(r) of 46,700. When expressed in oocytes, this enzyme functions as an NAD(+)-dependent 11 beta-dehydrogenase with very high affinity for steroids, but it has no detectable reductase activity. It is 37% identical in amino acid sequence to an NAD(+)-dependent isozyme of 17 beta-hydroxysteroid dehydrogenase but only 20% identical to the NADP(+)-dependent liver isozyme of 11-HSD. It is expressed at high levels in the kidney and adrenal and at lower levels in the colon. The corresponding gene is present in a single copy in the sheep genome. In humans, this gene is a candidate locus for the syndrome of apparent mineralocorticoid excess, a form of hypertension postulated to result from 11-HSD deficiency in mineralocorticoid target tissues.