ENANTIOSELECTIVE DEPLETION OF MITOCHONDRIAL GLUTATHIONE CONCENTRATIONS BY (S)-3-HYDROXY-4-PENTENOATE AND (R)-3-HYDROXY-4-PENTENOATE

(R,S)-3-Hydroxy-4-pentenoate rapidly and selectively depletes the mito chondrial glutathione pool in rat hepatocytes, but shows little cytoto xicity and does not induce mitochondrial dysfunction [Shan, X., et al. (1993) Chem. Res. Toxicol. 6, 75-81]. The objective of the present st udies was to investigate the 3-hydroxybutanoate dehydrogenase-dependen t oxidation of(R)- and (S)-3-hydroxy-4-pentenoate and the enantioselec tivity of 3-hydroxy-4-pentenoate-induced depletion of mitochondrial gl utathione concentrations in isolated rat liver mitochondria and hepato cytes. (S)-3-Hydroxy-4-pentenoate, but not (R)-3-hydroxy-4-pentenoate, was a substrate for 3-hydroxybutanoate dehydrogenase. Incubation of r at liver mitochondria or hepatocytes with (S)-3-hydroxy-4-pentenoate r esulted in a time- and concentration-dependent depletion of mitochondr ial glutathione concentrations, whereas (R)-3-hydroxy-4-pentenoate pro duced little depletion. These results show that (S)-3-hydroxy-4-penten oate is a substrate for 3-hydroxybutanoate dehydrogenase and is conver ted to the Michael acceptor 3-oxo-4-pentenoate, which reacts with glut athione and thereby depletes the mitochondrial glutathione pool. (S)-3 -Hydroxy-4-pentenoate may find use in the study of mitochondrial gluta thione homeostasis and the role of mitochondrial glutathione in cellul ar protection.