Xenobiotic Metabolism

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Michel Kranendonk

Principal Investigator



Campus Sant’Ana
Ed. CEDOC II, room 2.23
Pólo de Investigação NMS-UNL
Rua Câmara Pestana, nº 6
1150-082 Lisboa, Portugal
Email: michel.kranendonk_at_nms.unl.pt
Phone: +351 218 803 100 Ext 26047 (office) 20056 (lab)
Fax: + 351 218 803 010

Main Interests:

Main objective is the study of genetic variability in drug metabolism and its role in susceptibility to therapeutic drugs and environmental agents. This variability is a major determining factor in the beneficial and adverse effects in chemical exposure. Research concerns functional and mechanistic studies of drug metabolism enzyme variants to obtain insight in molecular mechanism of function of these enzymes, allowing the rationalization of their effect in exposure to agents and specific disease states. We focus mainly on human cytochrome P450, one of the most important enzyme families in drug metabolism.

Research areas

Functional studies of human cytochrome P450 enzymes

img1 xenob metabGenetic variants of the major P450 isoforms involved in xenobiotic metabolism are studied to understand the effect of their structural deviations on enzyme activity. These effects are interpreted by protein dynamics and protein:protein interactions, and can assist in the clarification of the function of the facultative protein cytochrome b5 in the enzyme complex.
from: Palma et al., Pharmacogenetics & Genomics. (2013), 23:41-52

Rare genetic disease – Antley-Bixler Syndrome (ABS)

img 2 xenob metab

Specific forms of ABS are thought to be due to deficient steroidogenesis and have been related to mutations in the human POR gene, encoding the cytochrome P450 reductase (CPR). Functional studies of these ABS-related CPR-proteins and their perturbed activity, allows not only to understand the underlying mechanism of this disease which is clinically relevant but also to gain insight in the molecular requisites of this protein in sustaining microsomal P450s in their activity.
from: Moutinho et al., Drug Metabolism and Disposition (2012) 40:754-60


Protein dynamics of P450 reductase (CPR) in electron-transfer

img 3 xenob metab

CPR is a multi-domain, redox-protein which sustains microsomal P450 activity by electron-transfer adapting specific conformations, transitioning between closed (electron loading, NADPH) and open structures (electron-donation, CPR:P450 interaction). The protein dynamics and structural requisites for the open-closed transformation in its gated electron donation are subjects of this research line.
from: Aigrain et al., EMBO Rep. (2009) 7:742-7


Human biotransformation and Bioactivation

img 4xenob metab

Adverse drug reactions (ADRs) are a major complication of drug therapy. The formation of reactive metabolites through biotransformation (bioactivation) is considered to be the major culprit in ADRs. This research-line concerns development of in vitro cell models, competent in human biotransformation, notably human P450, and their application in the detection (e.g. HT-screening) of reactive metabolites, in particular genotoxic or hard electrophilic intermediates.
from: Palma et al., Mutat Res. (2016), 806:24-33

As PI / Coordinator:

“Domain Dynamics and Control of Electron flux”; Agency Portuguese Foundation for Science and Technology (Fundação para a Ciência e a Tecnologia; FCT-ANR/MHC-CED/0002/2013); Period: 01/05/2014-31/04/2018

“The study of Antley-Bixler Syndrome related mutations of cytochrome P450 oxidoreductase: CYPOR polymorphism and the human cytochrome P450 enzyme complex”; Agency: Fundação para a Ciência e a Tecnologia; PTDC/SAU-GMG/71911/2006); Period: 03/01/2008-02/29/2012

As Integrated Member (2004-2017)

“Molecular and Cellular Effects of Human Mutations in Cytochrome P450 Reductase”; Agency: National Institute of General Medical Sciences; Type: 1-R01 (GM81568-01-04); Period: 04/01/2013-02/31/2017

“Bioactivation routes of the anti-HIV drug Nevirapine: identification of reactive metabolites and mutagenic potential; Agency: Fundação para a Ciência e a Tecnologia; (PTDC/QUI-QUI/113910/2009); Period: 01/02/2011-02/29/2013

“Molecular and Cellular Effects of Human Mutations in Cytochrome P450 Reductase”; Agency: National Institute of General Medical Sciences; Type: 1-R01 (GM81568-01-04); Period: 04/01/2008-03/31/2012.

McCammon KM, Panda SP, Xia C, Kim JJ, Moutinho D, Kranendonk M, Auchus RJ, Lafer EM, Ghosh D, Martasek P, Kar R, Masters BS, Roman LJ (2016) Instability of the human cytochrome P450 reductase A287P variant is the major contributor to its Antley-Bixler Syndrome-like phenotype. Journal of Biological Chemistry, 291: 20487-502.

Palma BB, Moutinho D, Urban P, Rueff J, Kranendonk M. (2016) Cytochrome P450 expression system for high-throughput real-time detection of genotoxicity: Application to the study of human CYP1A2 variants. Mutation Research, 806: 24-33.

B. Brito Palma, CW. Fisher, J. Rueff, M. Kranendonk (2016) Prototype Systems Containing Human Cytochrome P450 for High-Throughput Real-Time Detection of DNA Damage by Compounds That Form DNA-Reactive Metabolites. Chemical Research in Toxicology, 29: 747-56.

Kranendonk, M. Alves, M., Antune, P. and Rueff, J. (2014) Human sulfotransferase 1A1-dependent mutagenicity of 12-hydroxy-nevirapine: the missing link? Chemical Research in Toxicology, 27:1967-71.

Palma, B.B., Silva e Sousa, M. Urban, P. Rueff,J. Kranendonk M. (2013) Functional characterization of eight human CYP1A2 variants: the role of cytochrome b5. Pharmacogenetics & Genomics, 23:41-52.

D. Moutinho, CC. Marohnic, SP Panda, J Rueff, BS Masters, M Kranendonk. (2012) Altered human CYP3A4 activity caused by Antley-Bixler syndrome-related variants of NADPH-cytochrome P450 oxidoreductase measured in a robust in vitro system. Drug Metabolism and Disposition, 40:754-60

• Satya Panda, Linda Roman and Bettie Sue Masters, University of Texas Health Science Center at San Antonio, TX, US

• Gilles Truan and Phillipe Urban, National Institute of Applied Sciences, Toulouse, France

• Jeroen Kool and Nico Vermeulen, Vrije Universiteit Amsterdam, Netherlands