Background: Serum ornithine carbamoyltransferase is a diagnostic marker
of hepatic disorders due to its localization in periportal mitochondria.
Methods: We have developed a new method for the determination of serum
ornithine carbamoyltransferase. It is based on the reverse reaction of ornithine
carbamoyltransferase, using ornithine-ketoacid aminotransferase,
∆1-pyrroline-5-carboxylate dehydrogenase and glutamate dehydrogenase,
which together convert citrulline through ornithine to glutamate. The glutamate is
then quantitatively measured using glutamate oxidase and Trinder's reagent.
Results: The results obtained by this method agreed well with those
obtained using the diacetylmonoxime method as a gold standard [correlation
coefficient (r) = 0·973 P<0·001]. The endogenous amino acids sensitive to this
method in serum (glutamate, ornithine and ∆1-pyrroline-5-carboxylate) were
eliminated by the initial futile reaction. The new method appears to be more accurate
at low levels of ornithine carbamoyltransferase activity than the diacetylmonoxime
method.
Conclusions: Here we report a new method for serum ornithine
carbamoyl-transferase assay which might be useful for clinical diagnosis of hepatic
disorders, including hepatic cancer.
