title: Trehalose protects urea-induced unfolding of α-chymotrypsin.
abstract: Trehalose, a naturally occurring osmolyte, appears to be one of the most effective protectants for enzymes under various stress conditions while urea, a classical denaturant, destabilizes the activity, function, and alters the native structure of proteins. Herein, we have characterized the counteracting effects of trehalose on the deleterious effect of urea on α-chymotrypsin (CT) through the calorimetric data (transition temperature (T(m)), enthalpy change (ΔH), heat capacity change (ΔC(p)) and Gibbs free energy of unfolding (ΔG(u)) by using differential scanning calorimeter (DSC) and circular dichroism (CD) techniques, respectively, at a 1:2 ratio of trehalose and urea, as well as various urea concentration (up to 6 M) in the presence of 1 M trehalose. Our parallel experimental results explicitly elucidate that trehalose strongly offset the deleterious actions of urea on CT at 1:2 molar ratio of trehalose and urea, however, trehalose (1 M) some how failed to counteract the perturbation effects of urea (3-6 M) on CT.
authors.affiliation: Department of Chemistry, University of Delhi, Delhi 110007, India.
authors.forename: Awanish
authors.initials: A
authors.lastname: Kumar
authors.forename: Pankaj
authors.initials: P
authors.lastname: Attri
authors.forename: Pannuru
authors.initials: P
authors.lastname: Venkatesu
mesh_terms: D000818:Animals; D002152:Calorimetry, Differential Scanning; D002417:Cattle; D002918:Chymotrypsin / Q000737:chemistry* / Q000378:metabolism*; D008954:Models, Biological; D058767:Protein Unfolding / Q000187:drug effects*; D044366:Transition Temperature / Q000187:drug effects; D014199:Trehalose / Q000494:pharmacology*; D014508:Urea / Q000494:pharmacology*
chemical_list: D014508:Urea; D014199:Trehalose; D002918:Chymotrypsin; C117608:alpha-chymotrypsin