Purity: > 90% by SDS - PAGE Format: Liquid. In 20 mM Tris-HCl buffer (pH 8.0) containing 10% glycerol.. Calumenin, also known as CALu, is a multiple EF-hand calcium-binding protein located in endoplasmic reticulum(ER) and sarcoplasmic reticulum (SR) of mammalian tissues. This protein binds 7 calcium ions with a low affinity and is involved in such ER functions as protein folding and sorting. Recombinant human Calumenin protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography.