Polypeptide binding properties of the chaperone calreticulin

Calreticulin is a highly conserved eukaryotic ubiquitious protein located m ainly in the endoplasmic reticulum. Two major characteristics of calreticul in are its chaperone activity and its lectin properties, but its precise fu nction in intracellular protein and peptide processing remains to be elucid ated. We have investigated the interactions of human calreticulin with dena tured ovalbumin, proteolytic digests of ovalbumin, and different available peptides by solid phase assays, size-exclusion chromatography, capillary el ectrophoresis, and MS. The results show that calreticulin interacts better with unfolded ovalbumin than with native ovalbumin, that calreticulin stron gly binds components in proteolytic digests of denatured ovalbumin, and tha t calreticulin interacts strongly with certain synthetic peptides.