gamma-Glutamyl transferase isoenzymes in human bile.

Abstract

suMMARY The y-glutamyl transferase isoenzymes of bile were studied using electrophoretic, gel filtration, and ultracentrifugation techniques. In view of the known association of other biliary enzymes with lipids the effects of butanol extraction were investigated. The results show the presence of four isoenzymes of y-glutamyl transferase in bile, differing in electrophoretic mobilities, molecular size, and density. The correlation between the properties of biliary y-glutamyl transferase and of alkaline phosphatase is discussed.It has been recognised that there are several isoenzymes of y-glutamyl transferase (yGT) (E.C. 2.3.2.2.) present in the serum, although few attempts have been made to characterise them. In contrast, little attention has been paid to the presence of yGT in the bile, and the origin of the biliary isoenzymes has not been established.

Serum gamma-glutamyltransferase isoenzymes in extrahepatic biliary obstruction.

“…This author, studying yGT in liver extract, bile, and a normal serum pool, showed that papain digestion and incubation with detergent each produced a smaller molecule, corresponding to isoenzymes SV and S111, respectively, in this study. The detergent effect upon biliary yGT confirmed our previous demonstration (Wenham et al, 1978a) that extraction of biliary yGT with n-butanol resulted in the production of a smaller molecule possessing identical physicochemical characteristics to isoenzyme Sill (Table 2), a process similar to that already proposed for biliary alkaline phosphatase (Price et al, 1972).…”

“…In the case of yGT, it has been suggested that the biliary enzyme may be associated with lipid (Wenham et al, 1978a); furthermore, Beck (1978) suggested that a serum isoenzyme might be associated with a lipid component.…”

“…A study of the isoenzymes of yGT in the sera of patients with extrahepatic biliary obstruction was therefore undertaken, in relation to those isoenzymes already described in human bile (Wenham et al, 1978a), with a view to finding an explanation of the elevation in serum yGT activity observed in this group of patients. Received for publication 27 February 1979 Material and methods Sera were obtained from 10 patients with extrahepatic biliary obstruction, diagnosed at laparotomy or necropsy, and from nine laboratory staff who acted as normal controls.…”

“…Agar gel electrophoresis was performed on the Multiphor electrophoresis equipment (LKB Produkter, Bromma, Sweden) by a method already described (Wenham et al, 1978a).…”

Cortisol Regulation of Gamma-Glutamyl Transpeptidase in Liver, Choroid Plexus, Blood Plasma and Cerebrospinal Fluid of Developing Chick Embryo

“…The nature, source and functional impor tance of the soluble form of GGT in blood plasma and CSF is still uncertain, but the esti mation of this activity in serum and bile is a valuable index of hepatobiliary function and its alteration [12,26,35]. Serum GGT activ ity is also increased in patients with brain tu mors and some other neurological diseases [10,26].…”