What is the difference between Hot start polymerase and the taq polymerase - (Jun/18/2014 )

Dear All,

What is the difference between Hot start polymerase and the taq polymerase. 

Hot start polymerases are disabled (often with an antibody) so that they are inactive until released by a few minutes at 96-98. This avoids having to set up reactions on ice (which I have never done in any case), and allows reaction setup at room temperature. There are much better enzymes than Taq for most purposes, although Taq is perfectly fine for most uses and is very cheap.

Thanks so much, but there is no difference in terms of activity i.e they act the same way and with the same protocol ؟ 

They should do, although some hot start enzymes, especially the older ones require a lengthy activation step to remove the blocking agent.  The very first hot start enzymes used a chemical modification and I use one of these for a qPCR reaction which requires a 15min activation step - to remove the chemical modification.  The newer ones use antibodies which require less activation and the really new ones use aptamers which require activation steps of around 30 seconds.

Other than the activation step - the rest of the PCR reaction will be the similar as before - but look at the product insert to make sure you are using the optimal cycling conditions.