An Investigation of Interactions of Cytochrome B5 with Cytochrome P450s and Mechanisms of Cytochrome B5 on Cytochrome P450 Reactions PDF Download
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Author: Qiuxia Gao
Publisher:
ISBN:
Category :
Languages : en
Pages : 410
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Book Description
Author: Qiuxia Gao
Publisher:
ISBN:
Category :
Languages : en
Pages : 410
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Book Description
Author: David Cooper
Publisher: Springer Science & Business Media
ISBN: 1461590264
Category : Science
Languages : en
Pages : 550
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Book Description
P-450 has in common with our nation that it can call Phila delphia its hometown. Yet there are differences, too. The U. S. A. was born and named in this city. P-450 was first recog nized here -- an odd CO-combining pigment without family or func tion. Japanese workers identified it as an unusual member of the cytochrome family. Finally, in Philadelphia, its biological func tion was established and its growth to a global power initiated. Since discovery of its function as terminal oxidase of the 21-steroid hydroxylase system of adrenocortical microsomes, P-450 has proved to play the same role in a wide variety of other mixed function oxidase systems involved in biosynthesis and catabolism of specific cell or body components as well as in the metabolism of foreign substances entering organisms. P-450-like oxygenating enzymes appear to be fundamental cellular constituents in most forms of aerobic organisms. Activation of molecular oxygen and incorporation of one of its atoms into organic compounds as cata lyzed by P-450 enzymes are reactions of vital importance not only for biosynthesis and degradation of steroid hormones necessary for sustaining life, but also for metabolic activation or inactivation of foreign agents such as drugs, food preservatives and additives, insecticides and carcinogens. Moreover, P-450 linked enzyme sys tems can either be induced or suppressed by these agents with significant biological consequences.
Author: Chunsheng Zhao
Publisher:
ISBN:
Category :
Languages : en
Pages : 206
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Book Description
Cytochrome b5 (cyt b5 or holo b5) is known as one of the key components in the microsomal cytochrome P450 (CYP) monooxygenase system that metabolizes structurally diverse endogenous and exogenous compounds. It has been reported to modulate many CYPs activity and the effect is both CYP isoform and substrate dependent. However, to date no consensus has been made on the underlying mechanism. In the present study, the surface interactions between cyt b5 and major hepatic CYP isoforms 3A4, 2C9, 2A6 and 2D6 were investigated. Chemical cross-linking coupled with mass spectrometric analysis was used to identify the potential electrostatic interactions on protein surfaces of cyt b5 and CYPs. Subsequently, the interaction models of cyt b5-CYPs were built using these identified cross-linking sites as constraints. For the first time, holo b5 and apo b5 (cyt b5 devoid of heme) surface interactions with CYPs were compared. The models suggest both of them bind to the same the groove on CYPs with very small difference in their orientations. The closest distances between the heme groups of cyt b5 and each CYP isoform are beyond direct electron transfer distance, indicating that cyt b5 likely modulates these CYP isoforms activity through allosteric effect in addition to the potential electron transfer role. In order to confirm that the residues involved in cross-linking are functionally important for cyt b5-CYP interaction, site-directed mutagenesis of CYP3A4 were carried out with the identified Lys residues on CYP3A4 being substituted with neutral residue Ala. In addition, the importance of Arg446 on CYP3A4 at the interface of the cyt b5-CYP3A4 complex model was also accessed by single-point mutation. Mutation of these residues reduced or abolished cyt b5 binding affinity, suggesting that electrostatic interactions on the interface of the two protein are functionally important and the chemical cross-linking coupled with mass spectrometric analysis serves as a useful tool to study protein-protein interaction.
Author: David F. V. Lewis
Publisher: CRC Press
ISBN: 1420023047
Category : Medical
Languages : en
Pages : 223
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Book Description
Cytochromes are coloured iron-containing proteins that transfer electrons during cellular respiration and photosynthesis. The Cytochrome P450 family of enzymes catalyze reactions whereby water-insoluble drugs or metabolites, that would otherwise reach toxic levels in cell membranes, are rendered suitably water-soluble to leave the cell and be excreted in the urine. Due to the extensive nature of this subject, which is an area of intense scientific interest, the field is rapidly advancing and there is a need for new textbooks to keep abreast of the latest developments. The book fulfils that role in providing a fast-track approach for those coming into the P450 field, either at postgraduate level or in particular within the pharmaceutical industry. A Guide to Cytochrome P450 Structure and Function acts as an adjunct to the previous book Cytochromes P450: Structure, Function and Mechanism. It reviews the current status of the P450 field in terms of our present knowledge and understanding of the enzymes structure and function, including their multiplicity of forms, diversity of substrates, and selectivity. This is brought together with the latest research topics, including pharmacogenetics, regulation, human DMEs, toxicity screening and molecule modeling, to provide a fast-track approach for those new to the field.
Author: David F.V. Lewis
Publisher: CRC Press
ISBN: 0748404430
Category : Science
Languages : en
Pages : 344
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Book Description
This guide to the structure, function and mechanism of the cytochromes P450 focuses on the role of P450s in xenobiotic metabolism and toxicity. Colour illustrations show how modelling of P450s can rationalize their substrate specificity for the metabolism of both endogenous and exogenous chemicals.
Author: David F.V. Lewis
Publisher: Taylor & Francis
ISBN: 1135743282
Category : Science
Languages : en
Pages : 344
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Book Description
Author: Paul R. Ortiz de Montellano
Publisher: Springer
ISBN: 3319121081
Category : Medical
Languages : en
Pages : 912
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Book Description
This authoritative Fourth Edition summarizes the advances of the past decade concerning the structure, mechanism, and biochemistry of cytochrome P450 enzymes, with sufficient coverage of earlier work to make each chapter a comprehensive review of the field. Thirteen chapters are divided into two detailed volumes, the first covering the fundamentals of cytochrome P450 biochemistry, as well as the microbial, plant, and insect systems, and the second exclusively focusing on mammalian systems. Volume 1 begins with an exploration of the biophysics and mechanistic enzymology of cytochrome P450 enzymes, with a discussion of the structures of P450 enzymes and their electron donor partners, the mechanisms of oxygen activation and substrate oxidation, and the approaches and nature of cytochrome P450 inhibition. Two more chapters discuss the nature and roles of cytochrome P450 enzymes in microbes, plants and insects, and an eighth chapter is a survey of the potential utility of P450 enzymes in biotechnology. The first chapter of Volume 2 examines the roles of P450 enzymes in mammals, mainly humans. Four further chapters then deal with the genetic and hormonal regulation of P450 enzymes and their specific roles in the processing of sterols and lipids. Cytochrome P450: Structure, Mechanism, and Biochemistry is a key resource for scientists, professors, and students interested in fields as diverse as biochemistry, chemistry, biophysics, molecular biology, pharmacology and toxicology.
Author: David Cooper
Publisher: Springer
ISBN: 9780306390586
Category : Science
Languages : en
Pages : 0
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Book Description
P-450 has in common with our nation that it can call Phila delphia its hometown. Yet there are differences, too. The U. S. A. was born and named in this city. P-450 was first recog nized here -- an odd CO-combining pigment without family or func tion. Japanese workers identified it as an unusual member of the cytochrome family. Finally, in Philadelphia, its biological func tion was established and its growth to a global power initiated. Since discovery of its function as terminal oxidase of the 21-steroid hydroxylase system of adrenocortical microsomes, P-450 has proved to play the same role in a wide variety of other mixed function oxidase systems involved in biosynthesis and catabolism of specific cell or body components as well as in the metabolism of foreign substances entering organisms. P-450-like oxygenating enzymes appear to be fundamental cellular constituents in most forms of aerobic organisms. Activation of molecular oxygen and incorporation of one of its atoms into organic compounds as cata lyzed by P-450 enzymes are reactions of vital importance not only for biosynthesis and degradation of steroid hormones necessary for sustaining life, but also for metabolic activation or inactivation of foreign agents such as drugs, food preservatives and additives, insecticides and carcinogens. Moreover, P-450 linked enzyme sys tems can either be induced or suppressed by these agents with significant biological consequences.
Author: M.R. Waterman
Publisher: Springer Science & Business Media
ISBN: 3662030195
Category : Science
Languages : en
Pages : 235
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Book Description
Metabolic research and especially that which focuses on the monooxygenase cytochrome P450 system has gone through dramatic progressive changes within the last decade. Availability of highly sophisticated analytical techniques has contributed to increased molecular understanding of biotransformation pathways. Nowadays designer drugs are computer composable focussing on metabolic stability. The rapid development of recombinant enzymes has, in many cases, replaced the intensive work on P450 isolation from naturally occurring sources. Recombinant P450s can be expressed in cell lines and thus made available for reproducible and constant use addressig a large number of scientific questions. This book describes the present position of such research.
Author: Paul R. Ortiz de Montellano
Publisher: Springer Science & Business Media
ISBN: 0387274472
Category : Medical
Languages : en
Pages : 702
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Book Description
Cytochrome P450: Structure, Mechanism, and Biochemistry, third edition is a revision of a review that summarizes the current state of research in the field of drug metabolism. The emphasis is on structure, mechanism, biochemistry, and regulation. Coverage is interdisciplinary, ranging from bioinorganic chemistry of cytochrome P450 to its relevance in human medicine. Each chapter provides an in-depth review of a given topic, but concentrates on advances of the last 10 years.
