Pettigrew G W
Royal (Dick) School of Veterinary Studies, University of Edinburgh, U.K.
Biochim Biophys Acta. 1991 May 23;1058(1):25-7. doi: 10.1016/s0005-2728(05)80261-0.
The size, visible absorption spectra, nature of haem and haem content suggest that the cytochrome c peroxidase of Paracoccus denitrificans is related to that of Pseudomonas aeruginosa. However, the Paracoccus enzyme shows a preference for cytochrome c donors with a positively charged 'front surface' and in this respect resembles the cytochrome c peroxidase from Saccharomyces cerevisiae. Paracoccus cytochrome c-550 is the best electron donor tested and, in spite of an acidic isoelectric point, has a markedly asymmetric charge distribution with a strongly positive 'front face'. Mitochondrial cytochromes c have a much less pronounced charge asymmetry but are basic overall. This difference between cytochrome c-550 and mitochondrial cytochrome c may reflect subtle differences in their electron transport roles. A dendrogram of cytochrome c1 sequences shows that Rhodopseudomonas viridis is a closer relative of mitochondria than is Pa. denitrificans. Perhaps a mitochondrial-type cytochrome c peroxidase may be found in such an organism.
反硝化副球菌的细胞色素c过氧化物酶的大小、可见吸收光谱、血红素性质及血红素含量表明，它与铜绿假单胞菌的细胞色素c过氧化物酶相关。然而，反硝化副球菌的这种酶对具有带正电荷“前表面”的细胞色素c供体表现出偏好，在这方面类似于酿酒酵母的细胞色素c过氧化物酶。反硝化副球菌细胞色素c-550是所测试的最佳电子供体，尽管其等电点呈酸性，但其电荷分布明显不对称，“正面”带强正电荷。线粒体细胞色素c的电荷不对称性则不那么明显，但总体呈碱性。细胞色素c-550与线粒体细胞色素c之间的这种差异可能反映了它们在电子传递作用中的细微差别。细胞色素c1序列的系统发育树表明，绿色红假单胞菌比反硝化副球菌更接近线粒体。也许在这样的生物体中可以找到线粒体类型的细胞色素c过氧化物酶。
