Arillo A, Melodia F, Frache R
Istituto di Zoologia, Università di Genova, Italy.
Ecotoxicol Environ Saf. 1987 Oct;14(2):164-77. doi: 10.1016/0147-6513(87)90059-5.
The reduction of hexavalent chromium by rat liver mitochondria was studied under various experimental conditions. The occurrence of possible artifacts arising from inadequate methods for Cr(VI) detection was also tested. Erroneous results due to the presence of NAD(P)H (above 0.1 mM) could be demonstrated when the diphenylcarbazide method is employed. Modifications of this colorimetric procedure are proposed, in order to minimize artifacts occurring when Cr(VI) is detected in NAD(P)H-added mixtures. Although no interfering substances that can affect colorimetric methods are normally present in mitochondrial preparations, some methodological precautions are recommended. Mitochondria can reduce hexavalent chromium using either succinate or glutamate as electron donors. The succinate-supported reduction of Cr(VI) is active especially in the presence of ADP or an uncoupler, while reduction induced by glutamate occurs only in the presence of respiratory-chain inhibitors. In mitochondria supplemented by NAD-linked or FAD-linked substrates, different mechanisms in Cr(VI) reduction can therefore take place.
在各种实验条件下研究了大鼠肝线粒体对六价铬的还原作用。还测试了因六价铬检测方法不当而可能产生假象的情况。当采用二苯卡巴肼法时，可证明由于存在NAD(P)H（高于0.1 mM）会产生错误结果。为尽量减少在添加NAD(P)H的混合物中检测六价铬时出现的假象，提出了对此比色法的改进措施。尽管线粒体制剂中通常不存在会影响比色法的干扰物质，但仍建议采取一些方法上的预防措施。线粒体可以使用琥珀酸或谷氨酸作为电子供体来还原六价铬。琥珀酸支持的六价铬还原作用尤其在存在ADP或解偶联剂时具有活性，而谷氨酸诱导的还原作用仅在存在呼吸链抑制剂时发生。因此，在补充了NAD连接或FAD连接底物的线粒体中，六价铬还原可能会发生不同的机制。
