T7 RNA Polymerase is a DNA-dependent RNA polymerase that exhibits high specificity for the bacteriophage T7 promoter sequence 5"-TAATACGACTCACTATA-3". The enzyme can incorporate labeled or unlabeled nucleoside triphosphates into an RNA transcript. Large quantities of RNA can be synthesized from a DNA sequence cloned downstreamofthe T7 promoter due to the high processivity and transcription frequency of T7 RNA Polymerase. The enzyme is supplied in a buffer of 20 mM potassium phosphate (pH 7.9), 100 mM NaCl, 1 mM DTT, 0.1 mM EDTA and 50% glycerol.