Purification and heterogeneity of inorganic pyrophosphatase of pig scapula cartilage

Inorganic pyrophosphatase (pyrophosphate phosphohydrolase; EC 3.6.1.1) was purified from pig scapula cartilage by fractionation with N-cetylpyridinium chloride and (NH4)2SO4, followed by ion-exchange and gel-filtration chromatography. Enzyme preparations of high purity were obtained, with specific activities (100-400 units/mg) higher than those previously described for mammalian pyrophosphatases. The enzyme activity could be separated into several subfractions on ion-exchange columns.