PstI restrictase (Invitrogen) - reaction buffer (Nov/26/2005 )

Strange thing I found about Invitrogen's PstI restrictase description: in their "REact buffer compatibility" chart they indicate that its activity in REact 3 buffer is only 30%. At the same time, other suppliers indicate that activity of Pst I (cloned from the same source) in analogous buffer is 100% - f.i., according to Fermentas (Orange buffer) or NEB (NEBuffer 3). Does anybody know how can be this variance explained?

Well, I too am suprised there's such a big difference, but the buffers are not the same -- the NEB buffer contains 1 mM DTT, and the Fermentas buffer contains 0.1 mg/ml BSA. NEB also requires the addition of 0.1 mg/ml BSA to thier buffer 3, so they're using both DTT and BSA.