title: Characteristics of gamma-glutamyltranspeptidase in cultured skin fibroblasts from normals and cystinotics.
abstract: The characteristics of a fluorimetric method for assay of gamma-glutamyltranspeptidase (EC 2.3.2.2) in cultured human skin fibroblasts from normal donors and cystinotic patients using gamma-glutamyl-7-amino-4-coumarin as substrate are described. It is possible with this method to measure enzymatic activity in sonicates of cells with as little as 0.029 mmol/l L-cystine as acceptor-substrate with only 0.20 mg of cellular protein after 30--60 min of incubation. The properties of the enzyme in cells from patients with cystine storage disease show elevated gamma-glutamyltranspeptidase under various incubation conditions.
mesh_terms: D002478:Cells, Cultured; D002648:Child; D003374:Coumarins / Q000378:metabolism; D003553:Cystine / Q000378:metabolism; D003554:Cystinosis / Q000201:enzymology*; D005347:Fibroblasts / Q000201:enzymology; D006033:Glycylglycine / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D012867:Skin / Q000201:enzymology*; D005723:gamma-Glutamyltransferase / Q000378:metabolism*
chemical_list: D003374:Coumarins; C030988:gamma-glutamyl-7-amino-4-coumarin; D006033:Glycylglycine; D003553:Cystine; D005723:gamma-Glutamyltransferase