Isolation and Partial Characterization of 
Human CNS Axolemma-enriched Fractions

Much of what is known about the components and properties of nervous system proteins and lipids is derived from studies using biochemically isolated membrane fractions.  This paper was the first to describe the method for enrichment of fractions of axon membrane from human central nervous system (CNS) fibers.  In morphologically characterizing the axon membrane fraction and the two myelin membrane fractions, it was noted that biochemical isolation produces extensive modification and rearrangement of both the axon membrane and myelin sheath.  It also appeared that certain portions of the myelin sheath (the paranodal regions) were enriched with the axon membrane fraction rather than the myelin fractions.  This work was the foundation for further studies on the changes that occur during the isolation and enrichment of CNS membranes for biochemical analysis.