Enzymatic syntheses of carbamyl phosphate, L-citrulline, and N-carbamyl L-aspartate labeled with either 13N or 11C.
[13N]- and [11C]carbamyl phosphate, L-[omega-13N]citrulline, L-[ureido-11C]citrulline, [carbamyl-13N]- and [carbamyl-11C]carbamyl-L-aspartate were synthesized using carbamyl phosphate synthetase co-immobilized with either aspartate transcarbamylase or ornithine transcarbamylase. Carbamyl L-[13N]aspartate was enzymatically prepared from carbamyl phosphate and L-[13N]aspartate. The tissue distribution of radioactivity in mice after injection of radiolabeled ammonia, carbamyl phosphate or citrulline was studied. The tissue distribution of isotope derived from [13N]carbamyl phosphate and [13N]ammonia were similar, with the exception of liver, brain and pancreas, in which 13NH3 uptake was higher after retroorbital injection. The distribution of label derived from L-[omega-13N]- and L-[ureido-11C]citrulline was similar. Substantial tumor (Sarcoma-180) uptake of label from L-citrulline was observed.
D000818:Animals; D001221:Aspartate Carbamoyltransferase; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000378:metabolism; D002219:Carbamates / Q000138:chemical synthesis*; D002222:Carbamoyl-Phosphate Synthase (Ammonia); D002221:Carbamyl Phosphate / Q000138:chemical synthesis* / Q000378:metabolism; D002247:Carbon Isotopes; D002250:Carbon Radioisotopes; D002851:Chromatography, High Pressure Liquid; D002956:Citrulline / Q000138:chemical synthesis* / Q000378:metabolism; D005260:Female; D007553:Isotope Labeling / Q000379:methods; D051379:Mice; D008815:Mice, Inbred Strains; D009590:Nitrogen Radioisotopes; D009954:Ornithine Carbamoyltransferase; D011865:Radioisotope Dilution Technique; D014018:Tissue Distribution
D002219:Carbamates; D002247:Carbon Isotopes; D002250:Carbon Radioisotopes; D009590:Nitrogen Radioisotopes; D002956:Citrulline; D001224:Aspartic Acid; D002221:Carbamyl Phosphate; D001221:Aspartate Carbamoyltransferase; D009954:Ornithine Carbamoyltransferase; D002222:Carbamoyl-Phosphate Synthase (Ammonia); C006893:ureidosuccinic acid