VON Jagow G, Bohrer C
Biochim Biophys Acta. 1975 Jun 17;387(3):409-24. doi: 10.1016/0005-2728(75)90082-1.
The effect of antimycin on (i) the respiratory activity of the KCN-insensitive pathway of mitochondria of Neurospora grown on chloramphenicol (chloramphenicol-grown) with durohydroquinone and succinate or NADH as substrate, (ii) the electron transfer from the b-type cytochromes to ubiquinone with durohydroquinone as electron donor as well as (iii) the electron transfer from the b-type cytochromes to duroquinone with succinate as electron donor in chloramphenicol-grown Neurospora and beef heart submitochondrial particles was studied. All experiments were performed in the uncoupled state. 1. The respiratory chain of chloramphenicol-grown Neurospora mitochondria branches at ubiquinone into two pathways. Besides the cytochrome oxidase-dependent pathway, a KCN-insensitive branch equiped with a salicylhydroxamate-sensitive oxidase exists. Durohydroquinone, succinate or NADH are oxidized via both pathways. The durohydroquinone oxidation via the KCN-insensitive pathway is inhibited by antimycin, wheras the succinate or NADH oxidation is not. The titer for ful inhibition is one mol antimycin per mol cytochrome b-563 or cytochrome b-557. 2. The electron transfer from durohydroquinone to ubiquinone, which takes place in the KCN-inhibited state, does not occur in the antimycin-inhibited state. 3. The reduction of duroquinone by succinate in the presence of KCN is inhibited by antimycin. The titer for full inhibition is one mol antimycin per mol cytochrome b-566 or cytochrome b-562 for beef heart (or cytochrome b-563 or cytochrome b-557 for Neurospora). 4. When electron transfer from the b-type cytochromes to cytochrome C1, ubiquinone and duroquinone is inhibited by antimycin, the hemes of cytochrome b-566 and cytochrome b-562 (or cytochrome b-563 and cytochrome b-557) are in the reduced state. 5. The experimental results suggest that the two b-type cytochromes form a binary complex the electron transferring activity of which is inhibited by antimycin, the titer for full inhibition being one mol of antimycin per mol of complex. The electron transfer from the b-type cytochromes to ubiquinone is inhibited in a non-linear fashion.
（i）以杜罗氢醌和琥珀酸或NADH为底物，在氯霉素上生长的粗糙脉孢菌（氯霉素培养的）线粒体的KCN不敏感途径的呼吸活性；（ii）以杜罗氢醌为电子供体时，从b型细胞色素到泛醌的电子传递；以及（iii）在氯霉素培养的粗糙脉孢菌和牛心亚线粒体颗粒中，以琥珀酸为电子供体时，从b型细胞色素到杜罗醌的电子传递。所有实验均在解偶联状态下进行。1. 氯霉素培养的粗糙脉孢菌线粒体的呼吸链在泛醌处分支为两条途径。除了细胞色素氧化酶依赖途径外，还存在一条配备有水杨基羟肟酸敏感氧化酶的KCN不敏感分支。杜罗氢醌、琥珀酸或NADH可通过两条途径被氧化。通过KCN不敏感途径的杜罗氢醌氧化被抗霉素抑制，而琥珀酸或NADH氧化不受抑制。完全抑制的效价为每摩尔细胞色素b - 563或细胞色素b - 557一摩尔抗霉素。2. 在KCN抑制状态下发生的从杜罗氢醌到泛醌的电子传递，在抗霉素抑制状态下不发生。3. 在KCN存在下，琥珀酸对杜罗醌的还原被抗霉素抑制。牛心完全抑制的效价为每摩尔细胞色素b - 566或细胞色素b - 562一摩尔抗霉素（对于粗糙脉孢菌为每摩尔细胞色素b - 563或细胞色素b - 557）。4. 当抗霉素抑制从b型细胞色素到细胞色素C1、泛醌和杜罗醌的电子传递时，细胞色素b - 566和细胞色素b - 562（或细胞色素b - 563和细胞色素b - 557）的血红素处于还原状态。5. 实验结果表明，两种b型细胞色素形成一个二元复合物，其电子传递活性被抗霉素抑制，完全抑制的效价为每摩尔复合物一摩尔抗霉素。从b型细胞色素到泛醌的电子传递以非线性方式被抑制。
