Encyclopedia of Cancer

Living Edition
| Editors: Manfred Schwab

Phase II Enzymes

  • Yuesheng Zhang
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27841-9_4510-2



Phase 2 enzymes in principle are part of the cellular biotransformation machinery. Cellular biotransformation of xenobiotics and endobiotics, including carcinogens, may be divided into three sequential phases: phase 1 (oxidation, reduction, and hydrolysis reactions), phase 2 (conjugation reactions), and phase 3 (further modification and transport by efflux transporters). Phase 2 enzymes traditionally refer to the enzymes that catalyze the conjugation reactions of various substrates with endogenous ligands, such as glutathione S-transferase (GST), UDP-glucuronosyltransferase (UGT), N-acetyltransferase (NAT), and sulfotransferase (SULT). However, the term has gradually become broader in scope as it has also been used by an increasing number of investigators for a number of enzymes that catalyze phase 1 reactions, such as...


Epoxide Hydrolase Antioxidant Response Element Nrf2 Activation Cellular Antioxidant Capacity Light Subunit 
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See Also

  1. (2012) γ-Glutamylcystein synthetase. In: Schwab M (ed) Encyclopedia of cancer, 3rd edn. Springer, Berlin/Heidelberg, p 1559. doi:10.1007/978-3-642-16483-5_2437Google Scholar
  2. (2012) Chemoprevention. In: Schwab M (ed) Encyclopedia of cancer, 3rd edn. Springer, Berlin/Heidelberg, p 778. doi:10.1007/978-3-642-16483-5_1070Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  1. 1.Roswell Park Cancer InstituteBuffaloUSA