ENZYME ACTIVITIES IN CHICK EMBRYONIC CARTILAGE : Their Subcellular Distribution in Isolated Chondrocytes

Some characteristic enzymatic activities were determined in chick embryonic cartilage and compared with the analogous activities in bone and liver. Chondrocytes were isolated, broken by sonication, and subjected to subcellular fractionation to yield a nuclear pellet, the mitochondrial, lysosomal, and microsomal fractions, and the high speed supernatant solution. It was established that these fractions are characterized by enzymatic activities usually associated with similar fractions in other tissues, but with some quantitative differences. Lysozyme, a particulate-associated enzyme in other tissues, was not detected in any subcellular fraction even by the sensitive technique of microzone electrophoresis and is therefore considered to be primarily extracellular in cartilage.