These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Enzymes of pyrimidine biosynthesis in Crithidia luciliae.
    Author: Tampitag S, O'Sullivan WJ.
    Journal: Mol Biochem Parasitol; 1986 May; 19(2):125-34. PubMed ID: 2873507.
    Abstract:
    Evidence has been obtained for the presence of enzymes of both the de novo and salvage pyrimidine pathways in the protozoan parasite, Crithidia luciliae. Carbamyl phosphate synthetase-II activity could not be unequivocally demonstrated in crude extracts. However, a distinct peak of activity with a molecular weight of approximately 500 000 was observed following chromatography on Sepharose CL-6B. The enzyme preferentially utilised glutamine with respect to ammonia. It was inhibited by UTP and 5-phosphoribosyl-1-diphosphate had a small activating effect. Carbamyl phosphate synthesis by a 'phosphorolytic' citrullinase could not be demonstrated. The ensuing three de novo enzymes could also be separated on Sepharose CL-6B. Approximate molecular weights were estimated: aspartate transcarbamylase (150,000); dihydroorotase (90,000) and dihydroorotate dehydrogenase (70,000). As reported previously, orotate phosphoribosyltransferase and orotidylate decarboxylase were particulate, being associated with the glucosome. Activities of the salvage enzymes, uracil phosphoribosyltransferase, uridine phosphorylase and uridine nucleosidase were observed. All enzymes were cytoplasmic. No uridine kinase activity was detected.
    [Abstract] [Full Text] [Related] [New Search]