The occurrence of gamma-carboxyglutamate in a protein isolated from ox liver mitochondria.

A calcium-binding protein has been isolated from ox liver mitochondria. The purification procedure includes ammonium sulfate fractionation and chromatographies on Sephadex G-100 and DEAE-Sephadex, respectively. The isolated protein contains gamma-carboxyglutamate, has a molecular weight of 59,000, and an isoelectric point of about 3.8. By submitochondrial fractionation it was shown that the calcium-binding protein is located between the inner and outer mitochondrial membranes.