Hydrolysis and decomposition of chromium(III) and cobalt(III) complexes of adenosine 5'-triphosphate

Metal ion-promoted cleavage of mRNA 5′-cap models: hydrolysis of the triphosphate bridge and reactions of the N7-methylguanine base

“…The complex also appears to be rapidly inactivated under the experimental conditions, which has previously been attributed to irreversible formation of strong phosphate complexes. 25 Consistent with previously reported results, 14 Zn 2ϩ [12]aneN 3 is a rather poor catalyst in comparison to Cu 2ϩ complexes. Over the pH range studied, Cu 2ϩ BiPy promoted reactions, for example, are approximately a hundred times more efficient than those promoted by 13.…”

“…In contrast, values of 0.9 and 0.8 were obtained for the Cu 2ϩ BiPy promoted hydrolysis. A similar difference was observed between Cu 2ϩ [12]aneN 3 (12) and Cu 2ϩ [9]aneN 3 (11) ([9]aneN 3 = 1,4,7-triazacyclononane). The slopes of the plots log (k/s Ϫ1 ) vs. log (c/M) were 1.9 and 0.8, respectively (Table 1).…”

“…The slopes of the plots log (k/s Ϫ1 ) vs. log (c/M) were 1.9 and 0.8, respectively (Table 1). The slope also seems to be dependent on the substrate; in Cu 2ϩ [12]aneN 3 promoted reaction of AppA (4), the slope is clearly smaller than in reaction of 1 (Table 1).…”

“…Under these conditions the Cu 2ϩ BiPy -promoted reactions are faster than those promoted by the Cu 2ϩ TerPy- complex: the maximal rate constants obtained differ by a factor of 7. The pH-rate profile of the Zn 2ϩ [12]aneN 3 (13) promoted reaction consists only of four points, but it appears that the maximal rate is obtained at the same pH as with Cu 2ϩ TerPy, but the levelling off may be slightly less pronounced.…”

“…The effect of pH on the rate constants of the Cu 2ϩterpyridine (Cu 2ϩ TerPy, 9) promoted hydrolysis of diadenosine triphosphate (1), diphosphate (4) and tetraphosphate (5), and of the Cu 2ϩ -bipyridine (Cu 2ϩ BiPy; 10) and Zn 2ϩ -1,5,9triazacyclododecane (Zn 2ϩ [12]aneN 3 , 13) promoted reaction of 1 over a limited pH range from 5.5 to 8.5 is shown in Fig. 1.…”