S100 calcium-binding protein A1 (S100A1) is a small calcium binding protein with EF-hand structures and belongs to the S100 family. S100 proteins include at least 25 members which are located as a cluster on human chromosome 1q21. S100A1 is found in the heart, skeletal muscle, brain, and kidney.S100A1 mainly resides on the sarcoplasmic reticulum, mitochondria and myofilaments. S100A1 may function in stimulation of Ca2+-induced Ca2+ release, inhibition of microtubule assembly, and inhibition of protein kinase C-mediated phosphorylation. Reduced expression of this protein has been implicated in cardiomyopathies.Recombinant S100 calcium-binding protein A1 (S100A1) with His tag produced in E.coli is a single chain containing 101 amino acids with molecular mass of 11.5 kDa analyzed by reducing SDS-PAGE and is obtained by chromatographic techniques at GenScript.