Takaishi M, Shimizu T, Shishiba Y
Acta Endocrinol (Copenh). 1979 Dec;92(4):694-701. doi: 10.1530/acta.0.0920694.
The greater part of T3 is converted from T4 in liver or kidney. The majority of this activity exists in microsomal fraction. In the present study, we investigated whether this activity can be solubilized from rat liver microsomal pellet with various concentrations of deoxycholate (DOC). The extent of solubilization was compared with that of protein, rotenone insensitive NADH cytochrome c reductase or NADH cytochrome b5 reductase, which have been shown to associate with microsomal membrane rather than luminar contents. When 0.05% of DOC which was capable of releasing luminar contents of microsomal vesicles was applied to microsomal suspension, only a limited part of NADH cytochrome b5 reductase, rotenone insensitive NADH cytochrome c reductase or T4-5'-deiodinase activity was solubilized. When the concentration of DOC was increased to 0.125%, 41% of T4-5'-deiodinase activity was solubilized. Solubilization of protein, NADH cytochrome b5 reductase or rotenone insensitive NADH cytochrome c reductase was increased abruptly to 66%, 58% or 63%, respectively. The highest specific activity was obtained at 0.125% DOC. These results suggest that the T4-5'-deiodinase is associated with microsomal membrane instead of luminar contents.
大部分T3是在肝脏或肾脏中由T4转化而来。这种活性的大部分存在于微粒体部分。在本研究中，我们调查了这种活性是否能用不同浓度的脱氧胆酸盐（DOC）从大鼠肝脏微粒体沉淀中溶解出来。将溶解程度与蛋白质、鱼藤酮不敏感的NADH细胞色素c还原酶或NADH细胞色素b5还原酶的溶解程度进行比较，这些酶已被证明与微粒体膜而非腔内容物相关。当将能够释放微粒体囊泡腔内容物的0.05%的DOC应用于微粒体悬浮液时，只有有限部分的NADH细胞色素b5还原酶、鱼藤酮不敏感的NADH细胞色素c还原酶或T4-5'-脱碘酶活性被溶解。当DOC浓度增加到0.125%时，41%的T4-5'-脱碘酶活性被溶解。蛋白质、NADH细胞色素b5还原酶或鱼藤酮不敏感的NADH细胞色素c还原酶的溶解率分别突然增加到66%、58%或63%。在0.125% DOC时获得最高比活性。这些结果表明，T4-5'-脱碘酶与微粒体膜而非腔内容物相关。
