Although both Endonuclease V and Thermostable Endonuclease Q recognize deoxyinosine in DNA substrates that result in the formation of a nick with a 3′-OH and a 5′-phosphate, the location of the nick is different. Endonuclease V cleaves the second phosphodiester bond on the 3′ side of the deoxyinosine; Thermostable Endonuclease Q, cleaves on the phosphodiester bond immediately 5′ to the deoxyinosine. In addition, Endonuclease V activity is optimal at 37°C and can be heat-inactivated; Thermostable Endonuclease Q activity is optimal between 65°C and 85°C and cannot be heat-inactivated.
