Identification of calcium binding proteins from brain

A procedure was worked out for purification and identification of calcium-binding proteins from bovine brain using Ca²⁺-dependent, reversible binding to a hydrophobic support, phenyl-Sepharose, as the method of isolation. These proteins could be visualized during and after their separation by running them on non-denaturing polyacrylamide gels, blotting to Zeta-probe paper, and autoradiographing with⁴⁵Ca²⁺. About 24 polypeptides could be seen in this fraction on SDS (Laemmli) gels and about 8–10 native, Ca²⁺-binding proteins could be seen on non-denaturing gels and on blots of their 45Ca²⁺ autoradiographs. Some of these proteins could be purified further by chromatography on DEAE-Sephacel and still retain their⁴⁵Ca²⁺-binding activity.