title: Repression of rat kidney L-arginine:glycine amidinotransferase synthesis by creatine at a pretranslational level.
abstract: The first committed reaction in the biosynthesis of creatine is catalyzed by the enzyme L-arginine:glycine amidinotransferase, commonly called transamidinase. Creatine, the end product of the biosynthetic pathway, is known to alter the levels of kidney transamidinase activity. Rats fed a diet containing 0.3% creatine had 26% of the kidney transamidinase activity of the rats fed a creatine-free diet. This reduction in transamidinase activity was correlated with a decrease in transamidinase protein in the creatine-fed rats. The relative synthetic rates and mRNA functional activities of transmidinase were measured in control and creatine-fed rats. The relative synthetic rate of transamidinase in creatine-fed rats was 21% of that found in the control animals. The functional transamidinase mRNA in creatine-fed rats was correspondingly reduced to 37% of the amount in the control animals. Thus, creatine affects transamidinase activity by altering its rate of synthesis at a pretranslational step and represents an example of end-product repression in a higher eukaryote.
mesh_terms: D000579:Amidinotransferases / Q000096:biosynthesis* / Q000235:genetics; D000818:Animals; D003401:Creatine / Q000494:pharmacology*; D004032:Diet; D004591:Electrophoresis, Polyacrylamide Gel; D005470:Fluorometry; D005998:Glycine / Q000096:biosynthesis / Q000235:genetics; D007163:Immunosorbent Techniques; D007668:Kidney / Q000201:enzymology*; D008297:Male; D008970:Molecular Weight; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D012333:RNA, Messenger; D000579:Amidinotransferases; C020681:glycine amidinotransferase; D003401:Creatine; D005998:Glycine