Abstract

VAZQUEZ-CONTRERAS, Edgar; SANCHEZ-REBOLLAR, Brenda Guadalupe  and  CHANEZ-CARDENAS, María Elena. The Equilibrium Unfolding of Triosephosphate Isomerase from T. cruzi in Guanidinium Hydrochloride is a four State Process: Intrinsic Fluorescence Studies. Rev. Soc. Quím. Méx [online]. 2004, vol.48, n.4, pp.296-299. ISSN 0583-7693.

Equilibrium and kinetic folding pathways of several homologous proteins have been studied. Early studies concluded that the folding routes of homologous proteins follow fundamentally similar pathways, and that the folding of a certain conformation is conserved throughout evolution. However, there are examples of homologous proteins that unfold by different routes. Regarding triosephosphate isomerase (TIM), unfolding studies with enzymes from different sources, have shown: 1) two-state behaviors and 2) more complex processes (including two equilibrium-unfolding intermediates and inespecific aggregation), in the transition from de native homodimer to the denatured monomers. In this work, we studied the changes in intrinsic fluorescence of TIM from Trypanosoma cruzi after incubation in guanidinium hydrochloride. Our results show that the reaction is described by a four state process. Finally we discuss the results in terms of the heterogeneity observed in TIM denaturation.

Keywords : Triosephoshate isomerase; protein folding equilibrium intermediates.