Cellobiose oxidase from Phanerochaete chrysosporium Stopped‐flow spectrophotometric analysis of pH‐dependent reduction
Cellobiose oxidase from Phanerochaete chrysosporium Stopped‐flow spectrophotometric analysis of pH‐dependent reduction
复制标题
来自金孢原毛平革菌的纤维二糖氧化酶 pH 依赖性还原的停流分光光度分析
DOI：
10.1016/0014-5793(92)80991-o
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发表时间：
1992
期刊：
影响因子：
3.5
通讯作者：
K. Eriksson
中科院分区：
文献类型：
--
作者：
M. Samejima;Robert S. Phillips;K. Eriksson
纤维二糖氧化酶（CBO）能利用二氯酚靛酚（Cl_2Ind）和细胞色素作为有效的电子受体氧化纤维二糖。然而，这些电子受体的活性的pH依赖性是显着不同的。这两种化合物在pH 4.2时都是有效的电子受体，而只有二氯苯酚-靛酚在pH 5.9时具有活性。为了解释这一差异，通过停流分光光度法研究了纤维二糖对CBO中FAD和血红素还原速率的pH依赖性。在pH 4.2下，FAD和血红素都以高速率常数还原。相比之下，在pH 5.9时，只有FAD还原是快速的，而血红素的还原是极其缓慢的。因此，CBO对细胞色素的还原依赖于血红素，与FAD的还原相比，血红素在较低的pH范围内起作用。
Cellobiose oxidase (CBO) fromPhanetochaete chrysosporiumcan utilize dichlorphenol—indophenol (Cl2Ind) and cytochromecas effective electron acceptors for the oxidation of cellobiose. However, the pH dependencies of activity for these electron acceptors are significantly different. Both compounds act as effective electron acceptors at pH 4.2, whereas only dichlorophenol‐indophenol is active at pH 5.9. To explain this discrepancy, the pH dependencies of the reduction rates of FAD and heme, respectively, in CBO by cellobiose have been investigated by stopped‐flow spectrophotometry. Both FAD and heme are reduced with a high rate constant at pH 4.2. In contrast, at pH 5.9, only FAD reduction is fast, while the reduction of the heme is extremely slow. As a conclusion, the reduction of cytochromecby CBO is dependent on heme, which functions at a lower pH range compared to reduction of FAD.