Neurocan is the major soluble chondroitin sulfate proteoglycan in the brain. It is thought to play a functional role in axonal growth and guidance and in the establishment of specific neural pathways during embryonic brain development. Neurocan expression in the brain is developmentally regulated. Early on the major form of neurocan consists of a 245kD core protein with approximately two chondroitin sulfate glycosoaminoglycan chains of 22kD each. Later neurocan comprises a 180kD core protein