GTP hydrolysis by transitional endoplasmic reticulum from rat liver inhibited by all-trans-retinol.
GTP hydrolysis by an endoplasmic reticulum fraction from rat liver enriched in part-rough, part-smooth transition elements was inhibited by all-trans-retinol half maximally at a concentration of about 10 micrograms/ml. Similar results were obtained with GTPase activity partially purified by ion-exchange (DE-52) chromatography. The inhibition was non-competitive and given by both retinol and retinaldehyde but not by retinoic acid or alpha-tocopheryl acetate. The hydrolysis of other nucleoside di- and triphosphates was much less affected by retinol. The activity was inhibited by detergents but at much higher concentrations than by retinol. The results suggest that enhancement of cell-free transfer from endoplasmic reticulum to Golgi apparatus by retinol observed previously at low concentrations of cytosol may be mediated through an interaction with GTP.
Zhao
J G
JG
Department of Foods and Nutrition, Purdue University, West Lafayette, IN 47907.
Morré
D J
DJ
Paulik
M
M
Yim
J
J
Morré
D M
DM
D000818:Animals; D002852:Chromatography, Ion Exchange; D004721:Endoplasmic Reticulum / Q000201:enzymology*; D020558:GTP Phosphohydrolases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D051381:Rats; D014801:Vitamin A / Q000494:pharmacology*
D014801:Vitamin A; D006160:Guanosine Triphosphate; D020558:GTP Phosphohydrolases