Rat Epiphyseal Cartilage: I. Chemical Analysis and Isolation of Crude Protein-Polysaccharide.

Summary 1. The epiphyseal cartilage of 3- to 4-week-old rats has been analyzed for its constituents, DNA, RNA, hexosamine, uronic acid and hydroxyproline. An estimation of the total chemical nature of this cartilage is presented which suggests changes consistent with calcification. 2. Isolation of a crude PP from the epiphyses of 24–25-day-old animals is reported, which represents 20% of cartilage organic matrix and contains 72% of total cartilage uronic acid. Analysis of the reprecipitated PP reveals a molar ratio of hexosamine/uronic acid/nitrogen of 1.0/1.2/6.9, respectively. 3. The changes observed in PP type material isolated from older animals may be indicative of alterations occurring in PP in association with calcification.