and Abstract- The main goals of this proposal are 1) to provide the fundamental knowledge required for understanding Cytochrome P450 mediated reaction mechanism with regards to rates, regioselectivity, and binding, and 2) to provide computational tools for predicting the metabolic component of ADMET (Absorption, Distribution, Metabolism, Excretion, Toxicity). These are highly significant goals that will positively impact almost all drug development projects and decrease the time required to develop new therapeutics. These goals will be described in terms of the following four Specific Aims:
Aim 1) At present the number of active-oxygen species used by Cytochrome P450 remains controversial, and we propose that this may explain why predictive methods for metabolism are limited to around 85% accuracy. Predictive models for metabolism are important in drug design, and have the potential to save lives by decreasing the time it takes to develop new drugs.
Aim 2) Specific Aim 2 explores binding afforded to substrates designed to coordinate to the iron of the heme (type II binding) providing specificity for P450 enzymes by increasing affinity up to 250-fold. This is significant because systemic administration of drugs meant to inhibit a single P450 enzyme normally leads to broad inhibition of a number of P450 enzymes, upsetting homeostasis, and causing drug-drug interactions.
Aim 3) Computational prediction of P450 mediated rates remains one of the most important targets of researchers working in the field.
Specific Aim 3 will establish the features important in such predictions. If this goal can be met we can understand the important features involved in predicting the clearance of a drug from the body, and we move closer to the goal of virtual drug design.
Aim 4) With the ever-expanding number of computational methods and research publications in predictive ADMET, Specific Aim 4 will provide common sets of publicly accessible test set databases along with open-source predictive code allowing different computational ADMET methods to be tested against common benchmarks. This is particularly important since the majority of the methods are developed in-house and the test sets are not published. We hypothesize that by publishing open source code to a public web site for metabolic predictions that we can translate the results of ours'and others'research into the public domain resulting in a significant increase in the use and quality of these tools. We also hypothesize that having a common set of data available to all researchers will encourage validation, comparison, and enhancement of ADMET models. Public Health Relevance: Narrative- The purpose of this grant application is to understand the important features of cytochrome P450 enzymes with respect to drug metabolism, and drug design. Cytochrome P450 enzymes are the most important drug metabolizing enzymes and are responsible for most drug metabolism. While the majority of the reactions mediated by this enzymes family are benign, a number cause activation to reactive species that can cause cancer and toxicity. Furthermore, many life threatening drug-drug interactions occur from drugs slowing cytochrome P450 mediated reactions. This grant application will develop methods to design new drugs faster, and safer than we can presently through an increased understanding of the rates and binding affinities or P450 mediated reactions.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM084546-14
Application #
8102775
Study Section
Special Emphasis Panel (ZRG1-DIG-F (02))
Program Officer
Okita, Richard T
Project Start
1998-02-01
Project End
2013-06-30
Budget Start
2011-07-01
Budget End
2013-06-30
Support Year
14
Fiscal Year
2011
Total Cost
$315,029
Indirect Cost
Name
Washington State University
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
041485301
City
Pullman
State
WA
Country
United States
Zip Code
99164
Dahal, Upendra P; Joswig-Jones, Carolyn; Jones, Jeffrey P (2012) Comparative study of the affinity and metabolism of type I and type II binding quinoline carboxamide analogues by cytochrome P450 3A4. J Med Chem 55:280-90
Barr, John T; Jones, Jeffrey P (2011) Inhibition of human liver aldehyde oxidase: implications for potential drug-drug interactions. Drug Metab Dispos 39:2381-6
Jones, Jeffrey P; Joswig-Jones, Carolyn A; Hebner, Michelle et al. (2011) The effects of nitrogen-heme-iron coordination on substrate affinities for cytochrome P450 2E1. Chem Biol Interact 193:50-6
Dahal, Upendra P; Jones, Jeffrey P; Davis, John A et al. (2011) Small molecule quantification by liquid chromatography-mass spectrometry for metabolites of drugs and drug candidates. Drug Metab Dispos 39:2355-60
Pearson, Joshua; Dahal, Upendra P; Rock, Daniel et al. (2011) The kinetic mechanism for cytochrome P450 metabolism of type II binding compounds: evidence supporting direct reduction. Arch Biochem Biophys 511:69-79
Locuson, Charles W; Alfaro, Josh F; Zaya, Matthew J et al. (2011) A non-acidic sulfaphenazole analog demonstrating high intrinsic clearance and selectivity by canine CYP2C21. Drug Metab Lett 5:253-8
Peng, Chi-Chi; Pearson, Josh T; Rock, Dan A et al. (2010) The effects of type II binding on metabolic stability and binding affinity in cytochrome P450 CYP3A4. Arch Biochem Biophys 497:68-81
Hudelson, Matthew (2010) Vertex topological indices and tree expressions, generalizations of continued fractions. J Math Chem 47:219-228
Roberts, Kenneth M; Jones, Jeffery P (2010) Anilinic N-oxides support cytochrome P450-mediated N-dealkylation through hydrogen-atom transfer. Chemistry 16:8096-107
Alfaro, Joshua F; Joswig-Jones, Carolyn A; Ouyang, Wenyun et al. (2009) Purification and mechanism of human aldehyde oxidase expressed in Escherichia coli. Drug Metab Dispos 37:2393-8

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