HUMAN LIVER CALRETICULIN - CHARACTERIZATION AND ZN2+-DEPENDENT INTERACTION WITH PHENYL-SEPHAROSE

A 60-kDa human calreticulin was isolated from liver homogenates. The protein was identified as calreticulin by its NH2-terminal amino acid sequence, by its mobility in SDS-PAGE, by its immunoreactivity with anti-calreticulin antibodies, by its Ca2° binding, and by its localization to isolated ER membranes. In this study we show that Ca2° binding to calreticulin results in Ca2°-dependent aggregation and precipitation of the protein. We also show that calreticulin and calsequestrin bind Zn2° in 65Zn2° overlay. In addition we have discovered that calreticulin exhibits a Zn2°-dependent interaction with hydrophobic matrix of phenyl-Sepharose that can be utilized in the purification of the protein. © 1993 Academic Press, Inc.