Honjo K
Hokkaido Igaku Zasshi. 1984 Jul;59(4):439-45.
The terminal oxygenase of the NADH-depending lathosterol (cholest-7-en-3 beta-ol) 5-desaturase system was partially purified from rat liver microsomes, by Triton X-100 solubilization, DEAE-cellulose column chromatography, and hydrophobic affinity chromatography with Aminohexyl-Sepharose. The terminal oxygenase activity was approximately 18 fold greater than the starting microsome, and the yield was 18.4%, nevertheless, the terminal enzyme activity was almost free from other electron transfer components in microsomes. It was demonstrated that NADH, molecular oxygen, phospholipid, and three enzymes: NADH-cytochrome b5 reductase, cytochrome b5, and the terminal oxygenase, were absolutely essential for lathosterol 5-desaturation in the reconstituted system. Furthermore, the rate of the NADH-depending lathosterol 5-desaturation in the reconstitution system, was proportional to the concentration either of the terminal desaturase, cytochrome b5, or NADH-cytochrome b5 reductase, under conditions in which other enzymes were present in excess.
通过用Triton X-100增溶、DEAE-纤维素柱色谱法以及用氨基己基琼脂糖进行疏水亲和色谱法，从大鼠肝脏微粒体中部分纯化了依赖NADH的羊毛甾醇（胆甾-7-烯-3β-醇）5-去饱和酶系统的末端加氧酶。末端加氧酶活性比起始微粒体大约高18倍，产率为18.4%，然而，末端酶活性几乎不含微粒体中的其他电子传递成分。结果表明，在重组系统中，NADH、分子氧、磷脂以及三种酶：NADH-细胞色素b5还原酶、细胞色素b5和末端加氧酶，对于羊毛甾醇5-去饱和是绝对必需的。此外，在其他酶过量存在的条件下，重组系统中依赖NADH的羊毛甾醇5-去饱和速率与末端去饱和酶、细胞色素b5或NADH-细胞色素b5还原酶的浓度成正比。
