ABSTRACT
Trans-diamminedichloroplatinum(II) (trans-DDP) forms with DNA at 37 degrees C, more numerous interstrand cross-links than cis-DDP in the isolated DNA and DNA in the chromatin complex. An increase in the temperature to 42.5 degrees C had no effect on the interstrand cross-links of DND-Pt-DNA formed by the two isomers, both in DNA and in chromatin.
Subject(s)
Cisplatin/metabolism , DNA/metabolism , Animals , Cell Nucleus/metabolism , Chromatin/metabolism , Kinetics , Lymphocytes/metabolism , Spectrophotometry , Swine , ThermodynamicsABSTRACT
The aim of this work was to compare the kinetics of platinum binding to "naked" DNA and DNA remaining in a nucleoprotein complex. The incubation of chromatin and DNA from calf thymus was carried out with cis-DDP at different concentrations and incubation times. The coefficient rb/mumolPT/mumolDNA/ of platinum binding to DNA was determined and the kinetics of cis-DDP binding to particular preparations was found and compared. The presence of chromosomal proteins decreases the extent of DNA platination. Hence it can be suggested that this drug induces the process of chromatin aggregation and condensation which in turn reduce the release of the total pool of DNA.
Subject(s)
Chromatin/metabolism , Cisplatin/metabolism , DNA/metabolism , Animals , Cattle , Kinetics , Thymus Gland/metabolismABSTRACT
Malathion decreased polymerase activity of cell nuclei and inhibited RNA synthesis in cultured lymphocytes. The mechanism of action of this compound at the cellular level is suggested.
Subject(s)
Cell Nucleus/drug effects , DNA-Directed RNA Polymerases/antagonists & inhibitors , Lymphocytes/drug effects , Malathion/toxicity , Transcription, Genetic/drug effects , Cell Nucleus/enzymology , Cells, Cultured , Humans , Lymphocytes/metabolism , RNA/biosynthesisABSTRACT
Mono- and bifunctional complexes of cis DDP and d-guanosine were isolated on Sephadex G-25. The presence of cysteine in incubation mixture resulted in the vanishing of bifunctional complex of d-guanosine and the appearance of d-guanosine-cis DDP-cysteine complex in the eluted peak. It is also possible that the eluted peak contained no homogeneous product of the reaction.
Subject(s)
Cisplatin , Cysteine/pharmacology , Deoxyguanosine , Chemical Phenomena , Chemistry , Chromatography, Gel , Spectrophotometry, UltravioletABSTRACT
AF 8 cells are a mutant cell line of baby hamster kidney cells with a temperature-sensitive polymerase II activity. When these cells grow at the non-permissive temperature (40 degrees C) the syntheseis of low molecular weight RNA components D, C and A is preferentially inhibited, whereas the synthesis of rRNA, tRNA, 5 S RNA and component L is affected only a little or not at all. These results indicate that polymerase II catalyzes the synthesis of components D, C and A.
