The number and diversity of CYP clans, families, and subfamilies that an organism produces could correlate with its dietary breadth or specialization. Nevertheless, the set of interesting reactions being catalysed by these systems and the availability of new genetic engineering techniques allowing to heterologously express them and to improve and change their activity, stability and selectivity as well as the increasing interest of the industry in life sciences makes them promising candidates for biotechnological application in the future. Cytochrome P450s (CYPs) are xenobiotic detoxification genes found in most eukaryotes, and linked in insects to the tolerance of plant secondary chemicals and insecticide resistance. The structure-function relationships of cytochromes P450 are far from being well understood and their catalytic power has so far hardly been used for biotechnological processes. The present article describes some of the early events associated with the establishment of the biological function of P450s. The numbers of individual P450 enzymes in different species differ significantly, showing the highest numbers observed so far in plants. The diversity of the cytochrome P450 superfamily arose by an extensive process of gene duplications and by probable, but less well documented, cases of gene amplifications, conversions, genome duplications, gene loss and lateral transfers. Mammalian sequences within the same subfamily are always >55% identical. Members of the same gene family are defined as usually having > or =40% sequence identity to a P450 protein from any other family. More than 5000 different P450 genes have been cloned up to date (for details see: ). In all P450s, heme is bound in a structurally conserved protein core, allowing them to catalyze regioselective and stereoselective oxidation of hydrocarbons. Cytochrome P450: what have we learned and what are the future issues? Drug Metab. Cytochrome P450 proteins are enzymes that function in diverse pathways, from carbon source assimilation to hormone biosynthesis. Optimized chimeragenesis creating diverse P450 functions. 96, 2841-2888), (Werck-Reichhart, D., Feyereisen, R., 2000. Plants carry many cytochromes P450 CYP enzymes and then produce a huge array of chemicals, hence, metabolomics are of great importance in plant ecology. There is also a broad versatility of reactions catalysed by cytochromes P450 such as carbon hydroxylation, heteroatom oxygenation, dealkylation, epoxidation, aromatic hydroxylation, reduction, dehalogenation (Sono, M., Roach, M.P., Coulter, E.D., Dawson, J.H., 1996. This enzyme family is involved in the biotransformation of drugs, the bioconversion of xenobiotics, the metabolism of chemical carcinogens, the biosynthesis of physiologically important compounds such as steroids, fatty acids, eicosanoids, fat-soluble vitamins, bile acids, the conversion of alkanes, terpenes, and aromatic compounds as well as the degradation of herbicides and insecticides. They are hemoproteins encoded by a superfamily of genes converting a broad variety of substrates and catalysing a variety of interesting chemical reactions. Cytochromes P450 are ubiquitously distributed enzymes, which were discovered about 50 years ago and which possess high complexity and display a broad field of activity.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |