User:Jarle Pahr/Enzymes
Notes on various enzymes:
Polymerases (Not used in PCR. For polymerases used in PCR, see PCR page):
T4 DNA polymerase:
Posesses 5' -> 3 DNA polymerase and 3' -> 5' exonuclease activity. Used in SLIC. Does not show strand displacement activity. T4 DNA polymerase is active in NEBuffers 1-4 and NEB T4 DNA ligase buffer when supplemented with BSA.
T5 Exonuclease: A 5' -'3 exonuclease. Used in Gibson Assembly.
Klenow fragment: Fragment of E. coli DNA polymerase I, retaining 5'-3' polymerase activity and 3’ → 5’ exonuclease activity, but without 5' → 3' exonuclease activity. The 3'->5' exonuclease activity of the Klenow fragment is roughly 200 times less than that of T4 DNA polymerase (http://www.vivo.colostate.edu/hbooks/genetics/biotech/enzymes/t4dnap.html). Klenow fragment is commonly used to generate blunt ends by overhang fill-in. Klenow fragment is active in NEBuffers 1-4 and NEB T4 DNA ligase buffer. Klenow fragment can be heat-inactivated by incubation at 75C for 20 minutes.
T7 Exonuclease: 5'->3' exonuclease. Active in NEBuffer 4.
Lambda exonuclease: 5'->3' exonuclease. Unable to initiate digestion at nicks or gaps. Used with labmda exonuclease buffer.
See also the book Enzymes of molecular biology
and http://www.my-whiteboard.com/excellgen-commonly-used-enzymes/
Exonuclease III: http://en.wikipedia.org/wiki/Exonuclease_III
Used in a LIC-like procedure in this paper.
