Cytochrome P450 .

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Cytochrome P450. F.G. Guengerich S.D. Black T. Wolff, G. Strobl and H. Greim Sean Ekins F.J. Gonzalez. Lecture. Introduction to Cytochrome P450. Cytochrome P450 reactions Cytochrome P450 Structure P450 Substrates and Inhibitors prediction and design. Introduction.
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Cytochrome P450 F.G. Guengerich S.D. Dark T. Wolff, G. Strobl and H. Greim Sean Ekins F.J. Gonzalez

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Lecture Introduction to Cytochrome P450. Cytochrome P450 responses Cytochrome P450 Structure P450 Substrates and Inhibitors expectation and outline

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Introduction R.T. Williams - in vivo, 1947. Brodie – in vitro, from late 40s till the 60s. Cytochrome P450 proteins (hemoproteins) assume an imperative part in the intra-cell digestion system. Exist in prokaryotic and eukaryotic (plants creepy crawlies fish and warm blooded creature, and in addition microorganisms) Different P450 compounds can be found in any tissue: liver, kidney, lungs and even cerebrum. Assumes essential part in medications digestion system and xenobiotics.

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P450 Reactions Cytochrome P450 compounds catalyze a great many distinctive response. Oxidative responses. SH + O2 + NADPH + H+ SOH + H2O + NADPH+ The protein structure is accepted to decides the reactant specificity through complementarity to the move state.

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General Features of Cytochrome P450 Catalysis Substrate official (probably close to the site of the heme ligand) 1-electorn diminishment of the iron by flavprotein NADPH cytochrome P450 reductase Reaction of ferrous iron with O 2 to yield a precarious FeO 2 complex Addition of the second electron from NADPH or cytochrome b 5 Heterolytic scission of the FeO-O(H) attach to create a formal (FeO)3+ Oxidation of the substrate. Formal deliberation of hydrogen particle or electron Radical recombination Release of the item.

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Oxidative Reactions Carbon Hydroxylation Heteroatom Hydroxylation Heteroatom Release Rearangement Related to Heteroatom Oxidations Oxidation of π - System Hypervalent Oxygen substrate Reductive Reactions

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Humans CYP450 - 18 families, 43 subfamilies CYP1 tranquilize digestion system (3 subfamilies, 3 qualities, 1 pseudogene) CYP2 medication and steroid digestion system (13 subfamilies, 16 qualities, 16 pseudogenes) CYP3 sedate digestion system (1 subfamily, 4 qualities, 2 pseudogenes) CYP4 arachidonic corrosive or unsaturated fat digestion system (5 subfamilies, 11 qualities, 10 pseudogenes) CYP5 Thromboxane A2 synthase (1 subfamily, 1 quality) CYP7A bile corrosive biosynthesis 7-alpha hydroxylase of steroid core (1 subfamily part) CYP7B cerebrum particular type of 7-alpha hydroxylase (1 subfamily part) CYP8A prostacyclin synthase (1 subfamily part) CYP8B bile corrosive biosynthesis (1 subfamily part) CYP11 steroid biosynthesis (2 subfamilies, 3 qualities) CYP17 steroid biosynthesis (1 subfamily, 1 quality) 17-alpha hydroxylase CYP19 steroid biosynthesis (1 subfamily, 1 quality) aromatase frames estrogen CYP20 Unknown capacity (1 subfamily, 1 quality) CYP21 steroid biosynthesis (1 subfamily, 1 quality, 1 pseudogene) CYP24 vitamin D corruption (1 subfamily, 1 quality) CYP26A retinoic corrosive hydroxylase vital being developed (1 subfamily part) CYP26B likely retinoic corrosive hydroxylase (1 subfamily part) CYP26C probabvle retinoic corrosive hydroxylase (1 subfamily part) CYP27A bile corrosive biosynthesis (1 subfamily part) CYP27B Vitamin D3 1-alpha hydroxylase initiates vitamin D3 (1 subfamily part) CYP27C Unknown capacity (1 subfamily part) CYP39 obscure capacity (1 subfamily part) CYP46 cholesterol 24-hydroxylase (1 subfamily part) CYP51 cholesterol biosynthesis (1 subfamily, 1 quality, 3 pseudogenes) lanosterol 14-alpha demethylase

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Structure Till 2001 there was no warm blooded creature CYP. P450cam structure was fathomed in 1987 x-beam structure of P450cam with various substrate and inhibitors.

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Heme exists in hydrophobic environment, situated about parallel to the surfaces between the L and I helices. Heme-ligating Cys-357 (start of L) Helix-rich on the right side Beta-sheet-rich on the left side 14 alpha helices, 5 hostile to parallel beta-sheets Compact structure, particularly the helical district.

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Closed structure, conformational element is fundamental. No undeniable substrate channel. The range limited by B\' F/G and beta 5 recognized as the channel. 6 water particle fill the substrate dynamic site Substrate restricting circle buildups 80-103 Binding free vitality is doubtlessly because of hydrophobic connections of the substrate and the heme, Leu-244 and Val-295

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Structural Model for CYP450 Substrates and inhibitors Large number of medications concoction are as of now known Systematic endeavors to investigate substrate and inhibitor specificity of individual cytochrome P40 species

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Motivation Chemical poisonous quality studies Predict whether helpful impact might be subjected to individual varieties. Foresee drugs restraint.

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Elucidate Specificity approaches Determination of three dimensional structure of the dynamic site. Plan of pharmacophor: Molecular displaying Quantitative structure action relationship

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Three dimensional Structure of the Active Site In P450cam substrate authoritative, there are three districts of AA adaptability. One at the substrate restricting site Two are at the accepted substrate get to channel Backbone adaptability of P450cam if there should arise an occurrence of inhibitor official.

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Conclusions X-beam structure can serve as a fitting premise. Considering the level of adaptability at the dynamic site Water atom may oblige with the dynamic particle The improvement of novel substrate or solid inhibitors may be accomplished by docking tests, vitality minimization, sub-atomic elements, correlation of electrostatic potential allow.

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Design of Substrate Inhibitor Model Empirical Models Computer Aided Molecular Design of Pharmacophor Models

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Empirical Models Detect regular basic components by: Comprise stereochemical examination of metabolites Binding studies with substrate analogs Space-filling models Small number of substrates

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Computer Aided Molecular Design of Pharmacophor Models Quantitative Structure Activity Relationship Molecular Modeling

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Quantitative Structure Activity Relationship Computational science speaks to sub-atomic structures as a numerical models and reproduces their conduct with the conditions of quantum and traditional material science. Accessible projects empower researchers to effectively create and exhibit atomic information including geometries, energies and related properties (electronic, spectroscopic and mass). The typical worldview for showing and controlling these information is a table in which mixes are characterized by individual lines and sub-atomic properties (or descriptors) are characterized by the related segments. A QSAR endeavors to discover predictable connections between the varieties in the estimations of atomic properties and the natural action for a progression of mixes. A QSAR for the most part appears as a direct condition Biological Activity = Const + (C 1 P 1 ) + (C 2 P 2 ) + (C 3 P 3 ) + ... where the parameters P 1 through P n are processed for every atom in the arrangement. coefficients C 1 through C n are ascertained by fitting varieties in the parameters and the organic action.

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Molecular Modeling Utilizing computational systems to fabricate a pharmacophor by superimposing 3D structures of the ligands. Recognize low-vitality conformers. Recognize regular electrostatic elements. Structures are superimposed utilizing slightest squares fit techniques.

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3D QSAR of Cyp450 3A4 substrates

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