Conc. 10u/ul .T4 RNA Ligase catalyzes the ATP-dependent ligation of single-stranded RNA or DNA onto the 5´-phosphoryl termini of single-stranded RNA or DNA. The enzyme, purified from recombinant E. coli CA4 (RNase I-deficient). T4 RNA Ligase also catalyzes the addition of [5´-32P] nucleoside 3´,5´-bis (phosphate) onto single-stranded RNA.