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 present in GABAergic interneurons in the nervous system, predominantly expressed by chandelier and basket cells in the cortex. In the hippocampus, PV+ interneurons are subdivided into basket, axo-axonic, bistratified, and oriens-lacunosum moleculare (O-LM) cells, each subtype targeting distinct domains of pyramidal cells. Parvalbumin (PV) interneurons' connections are mostly perisomatic. Most of the PV interneurons are fast-spiking.