Bisson R, Montecucco C
FEBS Lett. 1982 Dec 13;150(1):49-53. doi: 10.1016/0014-5793(82)81302-1.
Two water-soluble carbodiimides, differing in molecular dimensions, have been used to characterize the cytochrome c binding site of bovine heart cytochrome c oxidase. Several polypeptide components of the enzyme contain acidic residues which are modified by these reagents. Carboxyl groups present in subunit II, VII and polypeptide c, are protected from modification when cytochrome c, equimolar to oxidase, is added and they can cross-link to the substrate once activated by the carbodiimide. Comparison of the modification patterns suggest that the most reactive residues are located on subunit II and VII, the former being also more exposed. The data obtained indicate that even though subunit II plays the major role in binding cytochrome c, at least two other lower Mr polypeptides contribute to the cytochrome c binding domain.
两种分子尺寸不同的水溶性碳二亚胺已被用于表征牛心细胞色素c氧化酶的细胞色素c结合位点。该酶的几个多肽组分含有可被这些试剂修饰的酸性残基。当加入与氧化酶等摩尔的细胞色素c时，亚基II、VII和多肽c中存在的羧基可免受修饰，并且一旦被碳二亚胺激活，它们就能与底物交联。修饰模式的比较表明，反应性最强的残基位于亚基II和VII上，前者也更暴露。所获得的数据表明，尽管亚基II在结合细胞色素c中起主要作用，但至少另外两个低分子量多肽对细胞色素c结合域有贡献。
