  Motivated by claims about the nature of the observed timescales in protein
systems said to fold downhill, we have studied the finite, linear master
equation which is a model of the downhill process. By solving for the system
eigenvalues, we prove the often stated claim that in situations where there is
no free energy barrier, a transition between single and multi-exponential
kinetics occurs at sufficient bias (towards the native state). Consequences for
protein folding, especially the downhill folding scenario, are briefly
discussed.
