FAQ: Which alkaline phosphatase, rSAP, CIP, or Antarctic Phosphatase, works best?

rSAP (NEB #M0371) is a superior choice because it combines the advantages of both CIP (NEB #M0290) and Antarctic Phosphatase (NEB #M0289). rSAP has a very high specific activity, comparable to CIP, with the advantage of being heat inactivatable, unlike CIP. rSAP is inactivated at 65°C, as is Antarctic Phosphatase, but rSAP is preferred over Antarctic Phosphatase because it does not require the user to add zinc or other co-factors. As a result, rSAP can be added directly to restriction enzyme digests. Additionally, after heat-inactivation of rSAP it is not necessary to purify vector DNA prior to the ligation reaction.