Immunochemical Characterization of Human β-D-N-Acetyl Hexosaminidase from Normal Individuals and Patients with Tay-Sachs Disease

An immunological distinction has been demonstrated between the two forms of human β-D-N-acetyl hexosaminidase (hexosaminidase A and hexosaminidase B). Absorption experiments indicate that a specific antigenic site (α) is present on hexosaminidase A and is either absent or masked on hexosaminidase B. In addition to the unique α-site, a second site (β)is also present on hexosaminidase A. The β-site is shared by both enzyme forms and appears to be responsible for the cross-reaction exhibited by these isoenzymes with unabsorbed antisera.