γ-Glutamyl Transpeptidase in Brain Capillaries: Possible Site of a Blood-Brain Barrier for Amino Acids

Science  05 Apr 1974:
Vol. 184, Issue 4132, pp. 66-68
DOI: 10.1126/science.184.4132.66


A fraction containing capillaries and rich in γ-glutamyl transpeptidase was isolated from homogenates of bovine brain cortex by density gradient centrifugation. The enzyme was localized in the endothelial cells by a histochemical procedure. γ-Glutantyl transpeptidase may function in the transfer of some amino acids across the blood-brain barrier.