Purine metabolism in Toxoplasma gondii

Journal Article · Sun Jun 25 00:00:00 EDT 1989 · J. Biol. Chem.; (United States)

OSTI ID:5767830

Krug, E C; Marr, J J; Berens, R L

We have studied the incorporation and interconversion of purines into nucleotides by freshly isolated Toxoplasma gondii. They did not synthesize nucleotides from formate, glycine, or serine. The purine bases hypoxanthine, xanthine, guanine, and adenine were incorporated at 9.2, 6.2, 5.1, and 4.3 pmol/10(7) cells/h, respectively. The purine nucleosides adenosine, inosine, guanosine, and xanthosine were incorporated at 110, 9.0, 2.7, and 0.3 pmol/10(7) cells/h, respectively. Guanine, xanthine, and their respective nucleosides labeled only guanine nucleotides. Inosine, hypoxanthine, and adenine labeled both adenine and guanine nucleotide pools at nearly equal ratios. Adenosine kinase was greater than 10-fold more active than the next most active enzyme in vitro. This is consistent with the metabolic data in vivo. No other nucleoside kinase or phosphotransferase activities were found. Phosphorylase activities were detected for guanosine and inosine; no other cleavage activities were detected. Deaminases were found for adenine and guanine. Phosphoribosyltransferase activities were detected for all four purine nucleobases. Interconversion occurs only in the direction of adenine to guanine nucleotides.

• Research Organization: Univ. of Colorado Health Sciences Center, Denver (USA)
• OSTI ID: 5767830
• Journal Information: J. Biol. Chem.; (United States), Vol. 264:18
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
PHOSPHOTRANSFERASES
ENZYME ACTIVITY
PURINES
METABOLISM
INOSINE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
AROMATICS
AZAARENES
ENZYMES
HETEROCYCLIC COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
RIBOSIDES
TRANSFERASES
550501* - Metabolism- Tracer Techniques