title: Cytochrome P450cin (CYP176A1).
abstract: Cytochrome P450cin (P450cin) (CYP176A1) is a bacterial P450 enzyme that catalyses the enantiospecific hydroxylation of 1,8-cineole to (1R)-6β-hydroxycineole when reconstituted with its natural reduction-oxidation (redox) partner cindoxin, E. coli flavodoxin reductase, and NADPH as a source of electrons. This catalytic system has become a useful tool in the study of P450s as not only can large quantities of P450cin be prepared and rates of oxidation up to 1,500 min(-1) achieved, but it also displays a number of unusual characteristics. These include an asparagine residue in P450cin that has been found in place of the usual conserved threonine residue observed in most P450s. In general, this conserved threonine controls oxygen activation to create the potent ferryl (Fe(IV=O) porphyrin cation radical required for substrate oxidation. Another atypical characteristic of P450cin is that it utilises an FMN-containing redoxin (cindoxin) rather than a ferridoxin as is usually observed with other bacterial P450s (e.g. P450cam). This chapter will review what is currently known about P450cin and how this enzyme has provided a greater understanding of P450s in general.
authors.affiliation: School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, Brisbane, 4072, Australia.
authors.forename: Jeanette E
authors.initials: JE
authors.lastname: Stok
authors.forename: Kate E
authors.initials: KE
authors.lastname: Slessor
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Farlow
authors.forename: David B
authors.initials: DB
authors.lastname: Hawkes
authors.forename: James J
authors.initials: JJ
authors.lastname: De Voss
mesh_terms: D003511:Cyclohexanols / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D000077591:Eucalyptol; D006900:Hydroxylation; D039821:Monoterpenes / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics / Q000378:metabolism; D009249:NADP / Q000235:genetics / Q000378:metabolism; D010084:Oxidation-Reduction
chemical_list: D003511:Cyclohexanols; D029968:Escherichia coli Proteins; D039821:Monoterpenes; D009249:NADP; D003577:Cytochrome P-450 Enzyme System; D009247:NADH, NADPH Oxidoreductases; C116041:flavodoxin NADPH oxidoreductase; D000077591:Eucalyptol