[2] The T7 polymerase also requires a double stranded DNA template and Mg2+ ion as cofactor for the synthesis of RNA.

[2] Similar to other viral nucleic acid polymerases, including T7 DNA polymerase from the same phage, the conserved C-terminal of T7 ssRNAP employs a fold whose organization has been likened to the shape of a right hand with three subdomains termed fingers, palm, and thumb.

[6] T7 polymerase is a representative member of the single-subunit DNA-dependent RNAP (ssRNAP) family.

[9] In biotechnology applications, T7 RNA polymerase is commonly used to transcribe DNA that has been cloned into vectors that have two (different) phage promoters (e.g., T7 and T3, or T7 and SP6) in opposite orientation.

The enzyme is stimulated by spermidine and in vitro activity is increased by the presence of carrier proteins (such as BSA).