Parvalbumin is a calcium-binding albumin protein with low molecular weight (typically 9-11 kDa). It has three EF hand motifs and is structurally related to calmodulin and troponin C. Parvalbumin is localised in fast-contracting muscles, where its levels are highest, and in the brain and some endocrine tissues. Parvalbumin is a small, stable protein containing EF-hand type calcium binding sites. It is involved in calcium signaling. Typically, this protein is broken into three domains, domains AB, CD and EF, each individually containing a helix-loop-helix motif.