I think you are confusing kinetics and equilibrium. Tm is an alternate
form of the _equilibrium_ constant, and as far as that's concerned denaturation
is the same as renaturation -- the constant is the same no matter which
reaction or what the concentration of DNA is. The _kinetics_, on the other
hand, are very different for the forward and reverse directions and will
be _very_ dependent on the total concentration of DNA as it is a 2nd
order reaction.
In other words, the concentration of DNA will determine how fast you get
there, but at Tm 50% of the DNA will be denatured regardless.
Keith "I hated PChem" Robison
Harvard University
Department of Cellular and Developmental Biology
Department of Genetics / HHMI
robison at ribo.harvard.edu
