20.BETA.-Hydroxysteroid dehydrogenase of neonatal pig testis. Localization in cytosol fraction and comparison with the enzyme from other species.
作者:SHIZUO NAKAJIN、SHUJI OHNO、MASAYUKI TAKAHASHI、KIYOSHI NISHIMURA、MASATO SHINODA
DOI:10.1248/cpb.35.2490
日期:——
20β-Hydroxysteroid dehydrogenase (20β-HSD) was found in neonatal pig testes. The enzyme catalyzed the reduction of 17α-hydroxyprogesterone to 17α, 2β-dihydroxy-4-pregnen-3-one with oxidation of nicotinamide adenine dinucleotide phosphate, reduced form (NADPH). Identification of 17α, 20β-dihydroxy-4-pregnen-3-one as the product was achieved by thin layer chromatography, gas chromatography, high-performance liquid chromatography, nuclear magnetic resonance spectroscopy and mass spectrometry. 20β-HSD activity was contained in the cytosol fraction of testis but not the microsomal or the mitochondrial fraction. Furthermore, the enzyme required the presence of NADPH or reduced nicotinamide adenine dinucleotide (NADH) as a cofactor, though NADH was far less effective than NADPH. The cytosol fraction of neonatal pig testis contained a large amount of 20β-HSD in comparison with that of mature pig testis. The 20β-HSD activity was also found in the cytosol fraction of mouse, rat, dog and guinea pig testes, but the activities were very low.
在新生猪睾丸中发现了 20β-羟类固醇脱氢酶(20β-HSD)。该酶催化 17α-羟基孕酮还原为 17α,2β-二羟基-4-孕烯-3-酮,并与还原型烟酰胺腺嘌呤二核苷酸磷酸酯(NADPH)发生氧化反应。通过薄层色谱法、气相色谱法、高效液相色谱法、核磁共振光谱法和质谱法,鉴定出 17α、20β-二羟基-4-孕甾-3-酮为产物。睾丸的细胞质部分含有 20β-HSD 活性,而微粒体或线粒体部分则没有。此外,该酶需要有 NADPH 或还原型烟酰胺腺嘌呤二核苷酸(NADH)作为辅助因子,但 NADH 远不如 NADPH 有效。与成熟猪睾丸相比,新生猪睾丸的细胞质部分含有大量的 20β-HSD。在小鼠、大鼠、狗和豚鼠睾丸的细胞质中也发现了 20β-HSD 活性,但活性非常低。