FIGURE 6.

The variation of the maximum entropy profiles of cytochrome c-TMR with sodium perchlorate concentration in the absence (a) and presence (b) of 3 m urea at pH 2. In the absence of urea, the maximum entropy profiles shift sharply toward lower diffusion time as I_C forms. This behavior of maximum entropy profiles is not consistent with the homopolymer collapse hypothesis. In the presence of urea, however, I_C forms slowly and gradually over an extended range of sodium perchlorate concentration, as expected for a homopolymer collapse.