AffiZYME® T4 DNA Ligase catalyzes the formation of phosphodiester bonds between juxtaposed 5' phosphate and 3' hydroxyl termini in blunt-end or sticky-end dsDNA. This product also can catalyze the ligation of RNA and ssDNA or RNA strands in double strands, but it cannot catalyze the ligation of whole single-stranded nucleotides. It is suitable for nucleic acid operations such as labeling RNA 3'-ends, circularizing RNA and DNA oligonucleotides or cloning cDNA.