RELATIONSHIP BETWEEN GAMMA-GLUTAMYL-TRANSPEPTIDASE ACTIVITY AND SIALIC-ACID CONTENT IN SOME ORGANS AND BRAIN-REGIONS OF THE DEVELOPING RAT

The activity of gamma-glutamyl transpeptidase (GGT) and the sialic aci d (SA) content were found to be specific in five brain regions of 7- a nd 50-day-old rats. While a low GGT activity was accompanied by high s ialylation in the whole brain a high GGT activity and low sialylation were observed in kidney and pancreas.;Similar findings were obtained f or some brain regions investigated. However, the developmental differe nces were not characterized by such relationship. Concanavalin A affin ity chromatography of GGT from brain of 7- and 50-day-old rats reveale d no remarkable changes in GGT sialylation although the almost 3 times higher in brain membranes of It can be concluded that in spite of an apparent relationship between GGT activity and membrane sialylation, t he amount of SA linked to the GGT molecule is not related to differenc es in enzyme activity,