STIMULATION OF ERYTHROCYTE-MEMBRANE MG2-ATPASE ACTIVITY BY GLUTATHIONE S-CONJUGATES()

Pig erythrocyte membrane Mg2+-ATPase activity was stimulated by variou s glutathione S-conjugates. For alkyl S-conjugates, the K-m for the st imulation was the lower, the more hydrophobic was the conjugate. 2,4-D initrophenyl-S-(N-acetyl)cysteine also stimulated the Mg2+-ATPase acti vity, suggesting a low specificity of the ''glutathione S-conjugate pu mp''. The K-m values for the stimulation by 2,4-dinitrophenyl conjugat es were lower than predictable on the basis of hydrophobicity which in dicates a high affinity of the transporter for these conjugates.