Talk:Addition of 3' A overhangs to PCR products
There's no need to purify the product after the PCR step if you want to directly clone into the TA vector. Invitrogen's protocol calls for addition of .5U of Taq for a 10 minute incubation @ 72C after the PCR is complete. It calls for a phenol extraction afterwards, but the product can be directly used to go into a TA vector ligation.
If the PCR product has already been purified, then this is an excellent protocol to follow.