Immunochemical cross reactivity of the antibody elicited against L-histidine decarboxylase purified from the whole bodies of fetal rats with the enzyme from rat brain

Rat cytosolic glutathione S-transferases catalyzed the conjugation of phenethyl chloride and phenethyl bromide with glutathione. The reaction proceeded with a high degree of stereoselectivity. The glutathione conjugate possessing the (R,S,S)- absolute configuration was formed in major quantities from the racemic substrates. The use of the enantiomers of the phenethyl chloride substrates indicated that the (S)-phenethyl chloride was conjugated in preference to the (R)-enantiomer. The conjugation proceeded with inversion of configuration at the benzylic carbon consistent with an SN₂-type mechanism. The stereoselectivity was greater for phenethyl chloride than for phenethyl bromide. Varying the substrate or enzyme concentration had no effect upon the observed stereoselectivity. The diastereomeric glutathione conjugates were separated by high performance liquid chromatography. These findings represent the first demonstration of the substrate stereoselectivity of the glutathione S-transferases.