the invention is directed to purified and isolated concanavalin a - binding proteins from chondrocytes that are not present in dedifferentiated cells from chondrocytes . the invention is also directed to a purified and isolated chondrocyte membrane protein , , which is a concanavalin a - binding protein , with a molecular weight of about 76 kd in sds - page . after treatment with endoglycosidase , cmp has an apparent molecular weight of about 67 kd . the n - terminal amino acid sequence and several internal amino acid sequences are given for cmp . these proteins can be used in assays , methods , or treatments involving differentiation of chondrocytes and the control of cartilaginous osteogenesis .