comparative study on the chaperone-like activity of camel and bovine beta -caseins

ABSTRACT

Molecular chaperones are characterized by a general behavior, arresting the exposed hydrophobic surfaces of denaturing substrate proteins. In the present study, the capacity of beta -caseins [beta -CN] from camel and bovine milk in suppression of thermal aggregation process of apo-yeast alcohol dehydrogenase [YADH] was assessed. Apo-I enzyme was prepared by removal of the structural zinc; while apo-II-protein was obtained by depleting conformational and catalytic zinc atoms. Fluorescence spectroscopy using ANS probe revealed greater hydrophobic surface in apo-II ADH. Considerable decrease in aggregation of the heat treated protein molecules was observed upon exposing to beta -CNs [camel, bovine]. Bovine beta -CN afforded more adverse effects on thermal aggregation. A direct correlation between casein's chaperone activity and structural stability of the substrate proteins was displayed. Moreover, an association between casein source and chaperone-like activity is suggested