Inhibition by CTP and UTP analogues of uridine kinase from mouse leukemic cells

Abstract

The new phosphonate analogues of CTP and UTP (CTPc and UTPc) inhibit the phosphorylation of uridine catalysed by uridine kinase in the presence of ATP and Mg2+-ions. The inhibition is competitive with respect to phosphate donor, and non-competitive with respect to phosphate acceptor. With respect to uridine the Ki constants for CTPc and UTPc are 7.5 . 10-5 mol l-1 and 1.0 . 10-4 mol l-1, respectively. With respect to ATP the Ki value for CTPc (3.6 . 10-6 mol l-1) is 3x lower than that for CTP. The novel analogues could be useful for further study of uridine kinase.