Glutathione S-transferases of human lung: Evidence that two distinct μ class subunits are expressed differentially in human population

These studies were focused on the μ class Glutathione S-transferase (GST) isozymes of human lung and demonstrate a variable expression of the μ class GST isozyme(s) in lung among human population. Western blot studies demonstrate that the μ class GSTs of human lung contain two subunits having approximate Mr values of 26,500 and 24,000. In lungs of different individuals, either one or both of these subunits were expressed in varying amounts. The individuals expressing both the subunits had two μ class GST isozymes having pI values of 6.25 and 6.45 in their lungs. Individuals expressing only the Mr 26,500 subunit had only the isozyme having pI 6.25 while those expressing only the Mr 24,000 subunits had only the isozyme having pI 6.45 in their lung. Both these μ class GSTs did not recognize the polyclonal antibodies against either the α or the π class human GST. Qualitative as well as quantitative variations among humans in the expression of the μ class GST isozymes in their lung would suggest differences in the detoxification capabilities of individuals for toxic compounds including carcinogens and may provide the molecular basis for differential toxicity towards carcinogens and other toxic compounds.