Extractability of lysozyme from bovine nasal cartilage

Abstract

Lysozyme (mucopeptide N-acetylmuramylhydrolase, EC 3.2.1.17) is present in the extracellular matrix of bovine nasal cartilage at a concentration of about 0.03 to 0.08 mg per g wet tissue (3-8 mg/100 ml per g). It is extracted from the tissue in guanidinium chloride solutions between 0.3 and 0.8 M. These concentrations are much lower than those which effectively extract most of the proteoglycans from the tissue, 2.5-3.0 M. Lysozyme migrates to the top of CsCl density gradients which are used to purify aggregated or monomer proteoglycan preparations; this suggests that lysozyme is not involved in the aggregation of proteoglycans in vitro. Chondroitinase from Proteus vulgaris effectively removes chondroitin sulfate from cartilage slices without solubilizing lysozyme which indicates that this highly anionic polysaccharide does not immobilize lysozyme in the matrix. Trypsin (EC 3.4.4.4) releases most of the chondroitin sulfate as well as 75% of the lysozyme from the matrix.