Mutant strains of Tetrahymena thermophila defective in thymidine kinase activity: Biochemical and genetic characterization
Three mutant strains, one conditional, of Tetrahymena thermophila were defective in thymidine phosphorylating activity in vivo and in thymidine kinase activity in vitro. Nucleoside phosphotransferase activity in mutant cell extracts approached wild-type levels, suggesting that thymidine kinase is responsible for most, if not all, thymidine phosphorylation in vivo. Thymidine kinase activity in extracts of the conditional mutant strain was deficient when the cells were grown or assayed or both at the permissive temperature, implying a structural enzyme defect. Analysis of the reaction products from in vitro assays with partially purified enzymes showed that phosphorylation by thymidine kinase and nucleoside phosphotransferase occurred at the 5' position. Genetic analyses showed that the mutant phenotype was recessive and that mutations in each of the three mutant strains did not complement, suggesting allelism.
- Research Organization:
- Dept. of Biology, York Univ., Downsview, Ontario M3J 1P3
- OSTI ID:
- 5823334
- Journal Information:
- Mol. Cell. Biol.; (United States), Vol. 2:8
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PHOSPHOTRANSFERASES
ENZYME INDUCTION
STRUCTURE-ACTIVITY RELATIONSHIPS
TETRAHYMENA
GENOME MUTATIONS
MUTANTS
BIOCHEMICAL REACTION KINETICS
DEFECTS
ENZYME ACTIVITY
GENETIC CONTROL
IN VITRO
IN VIVO
PHENOTYPE
PHOSPHORYLATION
THYMIDINE
ANIMALS
AZINES
CHEMICAL REACTIONS
CILIATA
CONTROL
ENZYMES
GENE REGULATION
HETEROCYCLIC COMPOUNDS
INVERTEBRATES
KINETICS
MICROORGANISMS
MUTATIONS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PEST CONTROL
PHOSPHORUS-GROUP TRANSFERASES
PROTOZOA
PYRIMIDINES
REACTION KINETICS
RIBOSIDES
TRANSFERASES
550400* - Genetics