initial velocity in an enzyme reaction - (Nov/14/2012 )
I was starting to get confused as well but I think we were essentially referring to the same part of a kinetics assay just with different terminology. It's because of today's assay sensitivity and rapid measurements that it can capture the single turnover of an enzyme which occurs in something like milliseconds (the burst kinetics). Then you see the initial velocity portion.
My guess would be that you were still measuring the correct initial velocity mdfenko and you wouldn't have seen the actual burst kinetics, so I don't think it invalidates any results from the 70's. From my knowledge, I think standard chromogenic or fluorescent protease assays (assuming you're hand pipetting) would be unlikely to see the actual burst phase, at least in my experience. Not sure if there any other enzyme biochemists out there who might be able to clarify this better for us?