Yang H S, Studebaker J F
Biotechnol Bioeng. 1978 Jan;20(1):17-25. doi: 10.1002/bit.260200103.
Whole cells of Pseudomonas testosteroni, induced to synthesize steroid-transforming enzymes beforehand, have been immobilized by entrapment in polyacrylamide gel. The immobilized cells have been used to catalyze the continuous delta1-dehydrogenation of Reichstein's substance S under various conditions in the presence of phenazine methosulfate (PMS), an electron acceptor for the cell-free delta1-dehydrogenase. The presence of PMS substantially increases the rate of reaction when fed with the steroid substrate to a continuous stirred tank reactor containing the immobilized cells. The operational half-life of the delta1-dehydrogenase activity of the cells, about 103 hr under the best operating conditions, is essentially unaffected by the presence of PMS. Though the acceleration of the reaction may be due to PMS-mediated passage of electrons from some component in the electron transport chain to molecular oxygen, the lack of a similar effect with methylene blue is consistent with the conclusion that PMS functions directly as the electron acceptor for the delta1-dehydrogenase.
预先诱导合成类固醇转化酶的睾丸酮假单胞菌全细胞，通过包埋在聚丙烯酰胺凝胶中实现固定化。在吩嗪硫酸甲酯（PMS，一种无细胞δ1-脱氢酶的电子受体）存在的情况下，固定化细胞已被用于在各种条件下催化 Reichstein 物质 S 的连续δ1-脱氢反应。当向含有固定化细胞的连续搅拌釜式反应器中加入类固醇底物时，PMS 的存在显著提高了反应速率。在最佳操作条件下，细胞δ1-脱氢酶活性的操作半衰期约为 103 小时，基本上不受 PMS 存在的影响。尽管反应加速可能是由于 PMS 介导电子从电子传递链中的某些成分传递到分子氧，但亚甲基蓝没有类似作用这一事实与 PMS 直接作为δ1-脱氢酶的电子受体这一结论一致。
