This antibody was raised against recombinant mouse parvalbumin. GP72 reacts specifically with parvalbumin on immunoblots of extracts of tissue originating from human, monkey, guinea pig, rabbit, rat, mouse and chicken (Fig. 1). The antibody specifically localizes parvalbumin using free-floating or mounted sections of brain (Fig. 2), kidney and muscles of probably all vertebrates The antiserum does not stain the brain of parvalbumin-KO mice. Spectacular staining found in immunohistochemistry on floating sections of 4% PFAfixed specimens.