INTERACTIONS OF POLYAMINES WITH MG2-SENSITIVE MACROELECTRODES AND MG2+ BUFFERS()

The polyamines spermine, spermidine and putrescine interact with Mg2+- sensitive macroelectrodes based on the neutral carrier ETH 7025; the i nteraction in decreasing order being spermine, spermidine and putresci ne. The effect is small and dependent on the ionized magnesium concent ration ([Mg2+](free)), only resulting in a significant increase in the measured [Mg2+](free) with spermine and spermidine at [Mg2+](free) le ss than 0.5 mM. The polyamines compete with Mg2+ for common binding si tes on Mg2+ buffers such as ATP, ADP and citrate, releasing bound Mg2 and increasing the [Mg2+](free). This effect is most prominent with M g ATP and the action of the polyamines in decreasing order is spermine , spermidine and putrescine. Increases in polyamines which occur in ce ll proliferation and cancer could thus secondarily increase the [Mg2+] (free) resulting in an activation of Mg2+-dependent metabolic pathways .