2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/28021We argue that the first order folding transitions of proteins observed at physiological chemical conditions end in a critical point for a given temperature and chemical potential of the surrounding water. We investigate this critical point using a hierarchical Hamiltonian and determine its universality class. This class differs qualitatively from those of other known models.3 pages RevTeX, 6 Postscript figuresSoft Condensed MatterChaotic DynamicsQuantitative Biologytext