Reversible inactivation of cytochrome P450 by alkaline earth metal ions: Auxiliary metal ion induced conformation change and formation of inactive P420 species in CYP101

Manna, Subal Chandra; Mazumdar, Shyamalava

doi:10.1016/j.jinorgbio.2008.01.013

Cited by 17 publications

(16 citation statements)

References 38 publications

(72 reference statements)

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“…The importance of magnesium chloride and other earth alkali metal ions in CYP mediated reactions was shown by Manna et al [121]. They proved that these ions play a major role in substrate binding, in stabilization of the active form of the enzyme and in electron transfer activity of the enzyme in presence of the substrate.…”

Section: Resultsmentioning

confidence: 97%

Comparison of Enzyme Kinetic Parameters Obtained In Vitro for Reactions Mediated by Human CYP2C Enzymes Including Major CYP2C9 Variants

Rokitta

Fuhr²

2010

CDM

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Cytochrome P450 (CYP) 2C enzymes contribute to the metabolism of about 30% of all drugs. Known polymorphisms of the respective enzymes and drug-drug interactions have a major impact on the efficacy and safety of some CYP2C substrate drugs. In vivo - in vitro correlations including prediction of the effect of such covariates requires quantitative information on enzyme kinetics. In this article there will be a summary of the values of the Michaelis-Menten constant (K(m)), the maximal velocity (V(max)) and the intrinsic clearance (Cl(int); V(max)/K(m)) for 84 substrates (100 reactions) reported to be mediated by CYP2C9 (variant enzymes CYP2C9.1, CYP2C9.2 and CYP2C9.3), CYP2C8 and/or CYP2C19. Particularly contradictory findings for the same reactions call for some standardization in the assessment of enzyme kinetics.

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Section: Resultsmentioning

confidence: 97%

Comparison of Enzyme Kinetic Parameters Obtained In Vitro for Reactions Mediated by Human CYP2C Enzymes Including Major CYP2C9 Variants

Rokitta

Fuhr²

2010

CDM

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“…Either way leads to the failure of forming the thiolate-ligated Fe 2+ species or to a distorted/weakened heme–thiolate bond, thus underlying the P450 → P420 transition [ 45 ]. Most P420 studies were performed with the P450 BM3 [ 52 , 54 ] or P450 cam [ 45 , 53 ] monooxygenases. These enzymes employ redox partner system to transfer electrons from NAD(P)H and activate O 2 as the oxidant, whose catalytic activity depends on the formation of a specific thiolate bond between the heme iron and the absolutely conserved cysteine residue in order to afford an active conformation state [ 33 ].…”

Section: Discussionmentioning

confidence: 99%

In vitro oxidative decarboxylation of free fatty acids to terminal alkenes by two new P450 peroxygenases

Ning

Yang

et al. 2017

Biotechnol Biofuels

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BackgroundP450 fatty acid decarboxylases represented by the unusual CYP152 peroxygenase family member OleTJE have been receiving great attention recently since these P450 enzymes are able to catalyze the simple and direct production of 1-alkenes for potential applications in biofuels and biomaterials. To gain more mechanistic insights, broader substrate spectra, and improved decarboxylative activities, it is demanded to discover and investigate more P450 fatty acid decarboxylases.ResultsHere, we describe for the first time the expression, purification, and in vitro biochemical characterization of two new CYP152 peroxygenases, CYP-Aa162 and CYP-Sm46Δ29, that are capable of decarboxylating straight-chain saturated fatty acids. Both enzymes were found to catalyze the decarboxylation and hydroxylation of a broad range of free fatty acids (C10–C20) with overlapping substrate specificity, yet distinct chemoselectivity. CYP-Sm46Δ29 works primarily as a fatty (lauric) acid decarboxylase (66.1 ± 3.9% 1-undecene production) while CYP-Aa162 more as a fatty (lauric) acid hydroxylase (72.2 ± 0.9% hydroxy lauric acid production). Notably, the optical spectroscopic analysis of functional CYP-Sm46Δ29 revealed no characteristic P450 band, suggesting a unique heme coordination environment. Active-site mutagenesis analysis showed that substitution with the proposed key decarboxylation-modulating residues, His85 and Ile170, enhanced the decarboxylation activity of CYP-Aa162 and P450BSβ, emphasizing the importance of these residues in directing the decarboxylation pathway. Furthermore, the steady-state kinetic analysis of CYP-Aa162 and CYP-Sm46Δ29 revealed both cooperative and substrate inhibition behaviors which are substrate carbon chain length dependent.ConclusionsOur data identify CYP-Sm46Δ29 as an efficient OleTJE-like fatty acid decarboxylase. Oxidative decarboxylation chemoselectivity of the CYP152 decarboxylases is largely dependent upon the carbon chain length of fatty acid substrates and their precise positioning in the enzyme active site. Finally, the kinetic mode analysis of the enzymes could provide important guidance for future process design.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-017-0894-x) contains supplementary material, which is available to authorized users.

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“…Complex pattern of stabilization and destabilization effects of Ca 2+ and Mg 2+ on CYP101 [131] have been attributed to their competitive binding to the K + sit but much less favorable coupling to the camphor binding. On the other hand, Ca 2+ and Mg 2+ have been reported to enhance catalysis in the membrane bound eukaryotic cytochromes P450, those involved in steroid biosynthesis [132] as well as xenobiotic metabolizing enzymes [10, 133].…”

Section: Allosteric Regulation In P450: K+ As An Allosteric Regulatormentioning

confidence: 99%

A novel type of allosteric regulation: Functional cooperativity in monomeric proteins

Denisov¹,

Sligar²

2012

Archives of Biochemistry and Biophysics

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Cooperative functional properties and allosteric regulation in cytochromes P450 play an important role in xenobiotic metabolism and define one of the main mechanisms of drugdrug interactions. Recent experimental results suggest that ability to bind simultaneously two or more small organic molecules can be the essential feature of cytochrome P450 fold, and often results in rich and complex pattern of allosteric behavior. Manifestations of non-Michaelis kinetics include homotropic and heterotropic activation and inhibition effects depending on the stoichiometric ratios of substrate and effector, changes in the regio- and stereospecificity of catalytic transformations, and often give rise to the clinically important drug – drug interactions. In addition, functional response of P450 systems is modulated by the presence of specific and non-specific effector molecules, metal ions, membrane incorporation, formation of homo- and hetero oligomers and interactions with the protein redox partners. In this article we briefly overview the main factors contributing to the allosteric effects in cytochromes P450 with the main focus on the sources of cooperative behavior in xenobiotic metabolizing monomeric heme enzymes with their conformational flexibility and extremely broad substrate specificity. The novel mechanism of functional cooperativity in P450 enzymes does not require substantial binding cooperativity, rather it implies the presence of one or more binding sites with higher affinity than the single catalytically active site in the vicinity of the heme iron.

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Reversible inactivation of cytochrome P450 by alkaline earth metal ions: Auxiliary metal ion induced conformation change and formation of inactive P420 species in CYP101

Cited by 17 publications

References 38 publications

Comparison of Enzyme Kinetic Parameters Obtained In Vitro for Reactions Mediated by Human CYP2C Enzymes Including Major CYP2C9 Variants

Comparison of Enzyme Kinetic Parameters Obtained In Vitro for Reactions Mediated by Human CYP2C Enzymes Including Major CYP2C9 Variants

In vitro oxidative decarboxylation of free fatty acids to terminal alkenes by two new P450 peroxygenases

A novel type of allosteric regulation: Functional cooperativity in monomeric proteins

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