Cysteine S-conjugate β-lyases are pyridoxal 5′-phosphate- containing enzymes that catalyze β-elimination reactions with cysteine S-conjugates that possess an electron-withdrawing group attached at the sulfur. The end products of the β-lyase reaction are pyruvate, ammonium and a sulfur-containing fragment. If the sulfur-containing fragment is reactive, the parent cysteine S-conjugate may be toxic, particularly to kidney mitochondria. Halogenated alkenes are examples of electrophiles that are bioactivated (toxified) by conversion to cysteine S-conjugates. These conjugates are converted by cysteine S-conjugate β-lyases to thioacylating fragments. Several cysteine S-conjugates found in allium foods (garlic and onion) are β-lyase substrates. This finding may account in part for the chemopreventive activity of allium products. This review (1) identifies enzymes that catalyze cysteine S-conjugate β-lyase reactions, (2) suggests that toxicant channeling may contribute to halogenated cysteine S-conjugate-induced toxicity to mitochondria, and (3) proposes mechanisms that may contribute to the antiproliferative effects of sulfur-containing fragments eliminated from allium-derived cysteine S-conjugates. © Springer-Verlag 2006.
CITATION STYLE
Cooper, A. J. L., & Pinto, J. T. (2006, February). Cysteine S-conjugate β-lyases. Amino Acids. https://doi.org/10.1007/s00726-005-0243-4
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