Search

The water-soluble proteinpolysaccharide of bovine nasal cartilage, called PPL, prevents sedimentation of freshly precipitating calcium phosphate below 1,000 x g but not above 10,000 x g. By a method recently described, PPL can be separated into several fractions of which the main ones are PPL-3 and PPL-5. PPL-5, but not PPL-3, resembles PPL in its capacity to inhibit calcium phosphate sedimentation. Precipitation of calcium phosphate in the presence of PPL can be used to separate it into three fractions: the first is associated with calcium phosphate sedimentable below 1,000 x g and resembles PPL-6; the second is associated with calcium phosphate sedimentable above 10,000 x g and resembles PPL-5; the third remains in the supernatant solution and is identical with PPL-3. Thus different fractions of PPL have widely different effects on calcium phosphate precipitation, and, conversely, calcium phosphate precipitation in the presence of PPL can separate it into different fractions. By the procedures described, an entity can be isolated containing 16% PPL-5 and 43% Ca3(PO4)2. Evidence is given which suggests that this may be a chemical compound. Adsorption of different forms of PPL to solid Ca3(PO4)2 seems to be nonspecific and not related to the effect described.