Active site of intestinal gamma-glutamyltransferase faces luminal side of brush border membrane.
Purified gamma-glutamyltransferase from hog small intestine was competitively inhibited by glutathione in vitro when L-gamma-glutamyl-p-nitroanilide was used as a substrate. An S-acetyldextran derivative of glutathione inhibited the enzyme as well as glutathione, although dextran had no inhibitory effect. gamma-Glutamyltransferase in the rat small intestine could utilize in situ L-gamma-glutamyl-p-nitroanilide circulated in the lumen, and was inhibited by the impermeable derivative of glutathione which was on the luminal side. These data suggested that the active site of intestinal gamma-glutamyltransferase faced the luminal side of the brush border membrane.
Nakamura
Y
Y
Azuma
T
T
Fukuyama
H
H
Suzuki
F
F
Nagata
Y
Y
D000814:Aniline Compounds / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D005978:Glutathione / Q000494:pharmacology; D007408:Intestinal Absorption; D007422:Intestines / Q000648:ultrastructure*; D008433:Mathematics; D008871:Microvilli / Q000201:enzymology; D013552:Swine; D005723:gamma-Glutamyltransferase / Q000037:antagonists & inhibitors / Q000378:metabolism*
D000814:Aniline Compounds; C008625:nitroaniline; D005723:gamma-Glutamyltransferase; D005978:Glutathione