Thermodynamics of the coil to frozen globule transition in heteropolymers

Recent analytic theories and computer simulations of heteropolymers have centered on the freezing transition of globular heteropolymers. We present a simple analytic theory to describe the coil to globule collapse in heteropolymers and compare this to the computer simulation of the exhaustive enumeration of all 18-mer cubic lattice polymer conformations. We find that the collapse transition from coil to frozen globule can either be first or second order. The relevance to protein folding is also discussed. (C) 1997 American Institute of Physics.