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)

Intravenous injection of praseodymium nitrate into female Wistar rats results in liver damage. The aim of this study is to investigate the quality of serum high density lipoprotein content as an index for the severity and time course of liver damage and regeneration following the administration of praseodymium. Serum high density lipoprotein content drastically decreases to a minimum after 24 - 48 h, returning to control values after four days. Liver degeneration is characterized by some intracellular parameters, i.e. the nuclear RNA polymerase reactions, the ribosomal protein synthesis, hepatic spermidine concentration and the activities of serum transaminases (GOT, GPT) and the sorbitdehydrogenase. From the data it is evident that the time course of serum high density lipoprotein content follows the intracellular changes closely. Liver regeneration is represented by the ornithin decarboxylase, the deoxycytidylate deaminase, the thymidine kinase activities and the hepatic putrescine content. The time course of these parameters shows that the regeneration reaches a maximum after 3 - 4 days. In the serum, high density lipoprotein content reflects this process by returning to control values. From our data we conclude that serum high density lipoprotein content after i.v. administration of praseodymium can be considered as an expression of the functional state of the liver.
 ...
PMID:Correlation between serum high density lipoprotein content and liver function during experimental hepatic degeneration and regeneration. 18 75

Present experimental data show that the synthesis of ribosomal protein S1 and PI protein was stimulated greatly by polyamines at the early stage after addition of putrescine in polyamine-requiring mutants of E. coli. No macromolecular synthesis was stimulated at this stage. Polyamine stimulation of the synthesis of these proteins probably plays an important role for cell growth. In polyamine-deficient bovine lymphocytes, protein synthesis became perturbed before RNA and DNA synthesis. Among enzymes concerned with DNA replication, thymidine kinase activity was most strongly influenced by polyamines. The activity in polyamine-deficient cells was only 7% of the level in normal cells. Judging from the amount of thymidine kinase mRNA and its distribution in polysomes, it was concluded that polyamines mainly regulate the synthesis of thymidine kinase at the level of initiation of protein synthesis. A polyamine-free protein synthetic system, established from components of rabbit reticulocytes, consisted of globin mRNA, salt-washed ribosomes, partially purified initiation factors, and pH 5 enzymes. Spermidine added to this system not only lowered the optimal magnesium concentration required for globin synthesis, but it also stimulated the globin synthesis 8- to 10-fold. The optimal spermidine concentration was 0.4 to 0.6 mM, a concentration similar to that in intact rabbit reticulocytes. The ratio of alpha to beta globin chains synthesized in the presence of spermidine and Mg2+ was approximately 1.0, while the ratio in the presence of only Mg2+ was approximately 1.5. The results strongly suggest that polyamines play an important role in rabbit reticulocyte protein synthesis.
 ...
PMID:Regulation of protein synthesis by polyamines. 307 28