Elevated specific activity of 5'-nucleotidase in a spinal cord myelin fraction from shiverer mice. Comparison with other myelin-associated enzymes and myelin proteins.

Myelin partially purified from spinal cords of dysmyelinating mutant (shiverer) mice had almost three-fold the specific activity of 5'-nucleotidase found in the respective myelin fraction from normal mice. The specific activities of two other normally myelin-associated enzymes, 2',3'-cyclic nucleotide-3'-phosphohydrolase and carbonic anhydrase, were only slightly higher in the myelin membranes from shiverers, compared to those from controls. In the mutants, the three enzymes probably occur in oligodendrocyte processes. Hypothetically, the 5'-nucleotidase in the myelin sheath in shiverer and normal mice may be localized in specialized structures.