Polymerases are available with proof reading activity. Which of the following are the characteristics of these types of polymerases?

 A. They add A residue at 3’ end

B. They are obtained from Thermococcus litoralis

C. They can’t be obtained from archaebacteria

D. The marine bacteria from which they are obtained grow at temperatures lower than that of Thermus aquatics

Explanation: As these polymerases are having a proof-reading activity, they generally don’t add any residue at the end. They are obtained from bacteria such as Thermococcus litoralis and grow at temperatures above than that of Thermus aquatics. They can also be obtained from archaebacteria.