Carbonic anhydrase and 2',3' cyclic nucleotide 3'-phosphohydrolase activity in normal human brain and in demyelinating diseases.

The activities of carbonic anhydrase and 2',3' cyclic nucleotide 3'-phosphohydrolase (CNPase) were measured in gray and white matter and in myelin from human brains obtained at autopsy. Carbonic anhydrase activity increased with age, and at all ages a major part of the activity was associated with membrane fractions. The percentage of membrane-bound carbonic anhydrase was lower than normal in white matter from Krabbe disease and adrenoleukodystrophy; isolated myelin had a low specific activity in these diseases. CNPase activity was decreased in both white matter and myelin, but was somewhat higher than normal in gray matter. Although the yield of myelin from a case of metachromatic leukodystrophy was markedly reduced, changes in the enzymes activities were minimal.