Activity of orotate metabolizing enzyme complex and various urea-cycle enzymes in mutant mice with ornithine transcarbamylase deficiency

Summary The overall activity of the enzyme complex consisting of orotate phosphoribosyl transferase and orotidine monophosphate decarboxylase, and of various enzymes of the urea cycle, has been studied in sparse-fur (spf) mutant mice with ornithine transcarbamylase deficiency. The enzyme complex has a lower overall activity, which could be caused by disturbed pyrimidine metabolism due to hyperammonemia. Other enzymes of the urea cycle do not show any significant change.Acknowledgments. The research was supported by a grant from the Conseil des Clubs Sociaux and Fondation Justine Lacoste Beaubien, Montréal. The authors wish to thank Ms Louise Poulin and Ms Francine Poisson for technical assistance.