Table 1. The first-order rate constant for the chemical ligation as described in Figures 2–5.

	k (×10−2·min−1)
pH	5΄-NH2 DNA	3΄-NH2 DNA	5΄-NH2 RNA	3΄-NH2 RNA
8.0	5.6	2.4	5.0	1.4
7.0	0.95	0.52	1.1	0.76
6.0	0.13	0.064	0.14	0.13