S100A1 is a small calcium-binding protein that plays critical roles in multiple processes, including Ca (2+) homeostasis and cardiomyocyte regulation. Elevated intracellular Ca (2+) triggers conformational changes in S100A1, thereby interacting with key proteins in cardiomyocytes such as RYR1, RYR2, ATP2A2 and F1-ATPase. S100A1 Protein, Human (C-His) is the recombinant human-derived S100A1 protein, expressed by E. coli , with C-6*His labeled tag.