Kinetic characteristics of the ATP-pyrophosphate isotope exchange catalyzed by RNA ligase from T4 bacteriophage
Zagrebel'nyĭ, S.N.; Zernov, I.P.; Knorre, D.G.
Molekuliarnaia Biologiia 18(1): 227-233
1984
ISSN/ISBN: 0026-8984 PMID: 6323974 Document Number: 239935
The dependence of initial rate v0 of ATP--PPi exchange reaction catalyzed by RNA-ligase of bacteriophage T4 on the concentration of ATP(s), pyrophosphate (z) and Mgcl2 has been determined. The dependence of v0 on s and z described by the equation v0 = k-1k2E0/(k-1 + K2) (1 + K1/s + k2/z) has been obtained for the reaction of E + S in equilibrium ES in equilibrium E1 + Z, where E--enzyme, E1--adenylylenzyme, S--ATP, Z--pyrophosphate, K1 and K2--constants of equilibrium, k-1, k2--velocity constants of transition of ES to E + S and E1 + Z, E0--complete concentration of enzyme. The low inhibition of the ATP--PPi exchange by the acceptor A(pA)2 and donors pAp, p(Ap)3, pCp has been shown. The dependence of v0 on the concentration of MgCl2 is consent with the incorporation of only dimagnesium salts of substrates in the isotope-exchange reaction.