Abstract
Treatment with methylglyoxal bis(guanylhydrazone), a specific inhibitor of S- adenosylmethionine decarboxylase (EC 4.1.1.50), suppressed the phytohemagglutinin-induction of [ 3H]thymidine uptake by guinea pig lymphocytes. The kinetics of [ 3H]thymidine uptake revealed that the K m value for thymidine was not changed, but the V value was markedly lowered by the methylglyoxal bis(guanylhydrazone) treatment. The induction of ATP : thymidine 5′-phosphotransferase (EC 2.7.1.75) (thymidine kinase) activity by phytohemagglutinin was suppressed to about the same extent as the induction of thymidine uptake. These suppressions were dependent on the methylglyoxal bis(guanylhydrazone) doses and on duration of the methylglyoxal bis(guanylhydrazone) treatment. Analysis of [ 3H]thymidine labelled compounds of the acid-soluble fraction showed that conversion of thymidine to thymidine 5′-triphosphate was inhibited by the methylglyoxal bis(guanylhydrazone) treatment. DNA polymerase activity was less inhibited by the methylglyoxal bis(guanylhydrazone) treatment in comparison with the methylglyoxal bis(guanylhydrazone) inhibition of thymidine uptake by whole cells. These results strongly suggested that blocking of polyamine accumulation by the methylglyoxal bis(guanylhydrazone) treatment influenced phytohemagglutinin induction of thymidine phosphorylation, resulting in a decrease of thymidine incorporation into DNA.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.