Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.1.21 (thymidine kinase)
 7,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of 5-azacytidine on tryptophan-mediated induction of various enzymes in rat livers was analyzed. Pretreatment of animals with 5-azacytidine results in a different response of tryptophan oxygenase to tryptophan and cortisone administration. While the hormonal induction of this enzyme was not affected by the drug, the tryptophan-mediated induction was stimulated. Pretreatment of rats with 5-azacytidine resulted also in the enhancement of liver tyrosine aminotransferase activity. There was no difference between the effect of tryptophan and cortisone. Tryptophan affects also the level of thymidine kinase at various stages of liver regeneration. 5-azacytidine given 16-40 hours prior to partial hepatectomy resulted in the enhancement of thymidine kinase activity at 24 hours of regeneration.
 ...
PMID:Tryptophan-mediated induction of hepatic enzymes stimulated by 5-azacytidine pretreatment. 616 9

In our previous study, an antimutagenic compound from spinach (Spinacea oleracea L.), ethoxy-substituted phylloquinone (ESP) was isolated and characterized. The current study deals with elucidation of the possible mechanism of antimutagenicity of ESP against ethyl methanesulfonate (EMS) deploying model systems such as human lymphoblast (TK+/- or TK6) cell line (thymidine kinase gene mutation assay) and Escherichia coli MG1655 (rifampicin resistance assay). Findings of the study ruled out the possibility of direct inactivation of EMS by ESP. DAPI competitive binding assay indicated the DNA minor groove binding activity of ESP. Interestingly, ESP did not display major groove binding or intercalating abilities. Further, proteomics study using 2-D gel electrophoresis in E. coli and subsequent studies involving single gene knockout strains revealed the possible role of tnaA (tryptophanase) and dgcP (diguanylate cyclase) genes in observed antimutagenicity. These genes have been reported to be involved in indole and cyclic-di-GMP biosynthesis, respectively, which eventually lead to cell division inhibition. In case of TK+/- cell line system, ADCY genes (adenylate cyclase), a functional analogue of dgcP gene, were found to be transcriptionally up-regulated. The generation/doubling time were significantly higher in E. coli or TK+/- cells treated with ESP than control cells. The findings indicated inhibition of cell proliferation by ESP through gene regulation as a possible mechanism of antimutagenicity across the biological system. Cell division inhibition actually provides additional time for the repair of damaged DNA leading to antimutagenicity.
 ...
PMID:Molecular mechanism of antimutagenicity by an ethoxy-substituted phylloquinone (vitamin K1 derivative) from spinach (Spinacea oleracea L.). 3281 Apr 88