USB Corporation reagents for various cloning applications include Tested User Friendly (TUF™) enzymes. T4 DNA Ligase is available in both low and high concentrations, allowing flexibility in ligation reactions. Heat-labile Shrimp Alkaline Phosphatase allows simple and rapid dephosphorylation of DNA ends useful for preventing unintended ligations. New OptiKinase™ provides uniform, consistent 5'-phosphorylation of oligonucleotides, independent of the base at the 5'-end (see figure). In addition, USB offers a growing line of RT, Taq and PCR reagents, including easy-to-handle single tube PCR and RT-PCR kits, along with Ultrapure PCR Nucleotides.