Changes with Age in Carbohydrate-Protein Complexes of Protein Polysaccharide Light Fraction of Rat Costal Cartilage

Abstract

Summary

Carbohydrate protein complexes of costal cartilage of rats, aged 3-4, 6, 10-13, and 20-27 months, were extracted with water and precipitated with EtOH in the presence of potassium acetate. The PPL was extracted with 0.15 M NaCl and separated into CMP and GP by the addition of (NH₄)₂SO₄ to 55% saturation. Ultracentrifugal analysis revealed that the CMP fraction consisted of approximately 90% 1.4 S and 10% 3.0 S components and the GP fraction was made up of equal amounts of 2.8 S and 3.8 S components. The protein: polysaccharide ratios are approximately 1:3 and 1:0.5 for CMP and GP, respectively. With increasing age, there were highly significant decreases of protein, uronic acid, hexose, and hexosamine in the PPL fraction. After separation of CMP and GP, this change is seen only in the CMP fraction.