Taq DNA Ligase catalyzes the formation of a phosphodiester bond in duplex DNA containing adjacent 5′-phosphoryl and 3′-hydroxyl termini, using NAD+ as a cofactor. The ligation will occur only if the oligonucleotides are perfectly paired to the complementary target DNA and have no gaps between them; therefore, a single-base substitution can be detected. This product is active at elevated temperatures (45°C-70°C) (1, 2).Applications Allele-specific gene detection by using Ligase Detection Reaction (LDR) and Ligase Chain Reaction (LCR) (1). Mutagenesis by incorporation of a phosphorylated oligonucleotide during primer extension amplification(3).