Molecular engineering of cytochrome P450 and myoglobin for selective oxygenations

Aspects of protein engineering of cytochrome P450 (P450) and myoglobin (Mb) to construct selective oxygenation catalysts have been described. Heme enzymes are known as biocatalysts for various oxidations but the design of substrate specificity has still remained one of the significant challenges because of dynamic nature of enzyme-substrate interactions. In particular, P450s are the most interesting targets among the heme enzymes because they are able to catalyze many types of monooxygenations such as hydroxylation, epoxidation, and sulfoxidation with high selectivity. Thus, many researchers have made efforts to convert the selectivity for natural substrates into that for unnatural substrates by several protein engineering approaches. On the other hand, we have reported a rational design of Mb to convert its oxygen carrier function into that of peroxidase or peroxygenase. The Mb mutants prepared in our work afford oxo-ferryl porphyrin radical cation (compound I) as observable species in Mb for the first time. Furthermore, some of the mutants we have constructed are useful for enantioselective oxygenations by oxygen transfer from the Mb-compound I to substrates. Copyright (c) 2004 Society of Porphyrins & Phthalocyanines.