Effect of polyamines on protein kinases activities from Trypanosoma cruzi

An interaction of polyamines with protein kinases activities from T. cruzi epimastigotes is demonstrated. Spermine and spermidine and less pronounced putrescine are found to inhibit protein kinases activities. In the extract of T. cruzi three protein kinases are distinguished on account of molecular weight (greater than 200 000, 95 000 and 40 000) and preference for acceptor proteins (phosvitin and histones). Especially the activity of the high molecular weight protein kinase which phosphorylates phosvitin is strongly inhibited by spermine and spermidine. The type of inhibition by both polyamines is found to be non-competitive with respect to ATP as well as phosvitin. The inhibition constants for spermine and spermidine are determined to be 1.4 mM and 2.0 nM, respectively.