Molecular approaches for production of pravastatin, a HMG-CoA reductase inhibitor: transcriptional regulation of the cytochrome p450sca gene from Streptomyces carbophilus by ML-236B sodium salt and phenobarbital

Cytochromes P450 as promising catalysts for biotechnological application: chances and limitations

Cytochromes P450 (CYPs) belong to the superfamily of heme b containing monooxygenases with currently more than 21,000 members. These enzymes accept a vast range of organic molecules and catalyze diverse reactions. These extraordinary capabilities of CYP systems that are unmet by other enzymes make them attractive for biotechnology. However, the complexity of these systems due to the need of electron transfer from nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) via redox partner proteins for the initial hydroxylation step limits a broader technical implementation of CYP enzymes. There have been several reviews during the past years tackling the potential CYPs for synthetic application. The aim of this review is to give a critical overview about possibilities and chances for application of these interesting catalysts as well as to discuss drawbacks and problems related to their use. Solutions to overcome these limitations will be demonstrated, and several selected examples of successful CYP applications under industrial conditions will be reviewed.

Cholesterol, an essential molecule: diverse roles involving cytochrome P450 enzymes

Cholesterol is an essential molecule for eukaryotic life and is an important precursor for a wide range of physiological processes. Biosynthesis and homoeostasis of cholesterol are complex mechanisms that are tightly regulated and interlinked with activities of a number of cytochrome P450 enzymes. These P450s play central critical roles in cholesterol metabolism. Key roles include a rate-limiting reaction in the synthesis of cholesterol itself, and in the oxidative transformations of cholesterol into steroid hormones and bile acids. However, microbial P450s also have important roles that impinge directly on human cholesterol synthesis and oxidation. Recent data reveal that Mycobacterium tuberculosis (which infects more than one-third of the world's human population) uses P450s to initiate breakdown of host cholesterol as an energy source. Microbial P450s also catalyse industrially important transformations in the synthesis of cholesterol-lowering statin drugs, with clear benefits to humans. The present article reviews the various roles of P450s in human cholesterol metabolism, from endogenous P450s through to microbial oxidases that enable catabolism of human cholesterol, or facilitate production of statins that regulate cholesterol production with positive outcomes in cardiovascular disease.

Efficient bioconversion of compactin to pravastatin by the quinoline-degrading microorganism Pseudonocardia carboxydivorans isolated from petroleum-contaminated soil

Pravastatin is one of the first available statins on the market. The purpose of this study was to isolate and identify the quinoline-degrading microorganism from petroleum-contaminated soil that could bioconvert compactin to pravastatin. There were 10,011 microorganism colonies isolated; five strains showed a higher capability for quinoline biodegradation. These five strains were evaluated for their pravastatin bioconversion ability; Pseudonocardia sp. had the highest efficiency for conversion of compactin to pravastatin. The strain was further identified as Pseudonocardia carboxydivorans PAH4. The bioconversion rates were studied under difference incubation conditions. Pre-incubation in medium containing 0.005% compactin sodium, resulted in the compactin utilization rate of almost 100% in a 1mg/ml compactin-containing medium. The rate of conversion of pravastatin was up to 68% after 6 days of incubation. In conclusion, the results of this study suggest that P. carboxydivorans PAH4 could be considered a candidate for the production of pravastatin on an industrial scale.