Isolation of acidic Ca
buffering proteins from
. Stains-all staining of SDS-PAGE (10-12.5% polyacrylamide linear gradient gel). Acidic proteins which bind Ca2+, such as calsequestrin and calreticulin, stain blue with Stains-all, whereas other proteins stain pink . Lane 1, M. loti crude extracts (50 μg); lane 2, soluble fraction (50 μg); lane 3, protein sample after selective precipitation with ammonium sulphate (50 μg); lane 4, calsequestrin purified from rabbit skeletal muscle, used as a positive control (1 μg). Arrow, M. loti Stains-all blue-staining band with an apparent molecular mass of 20 kDa; arrowhead, rabbit calsequestrin.