The conversion of the precursor form of gamma-glutamyltranspeptidase to its subunit form takes place in brush border membranes.

The subcellular distributions of the precursor form and mature form of gamma-glutamyltranspeptidase of rat kidney were studied by labeling the enzyme with [3H]fucose in vivo. In trans Golgi elements and basolateral membranes, gamma-glutamyltranspeptidase was present as a precursor form with a single polypeptide chain. However, the brush border membranes contained the heavy and light subunits as well as precursor. These results suggest that the precursor is converted to the mature form after its transport to the brush border membranes.