Heterogeneity of carbonic anhydrase and 68 kDa neurofilament in nerve roots analyzed by two‐dimensional electrophoresis

The heterogeneity of carbonic anhydrase (CA) and 68 kDa neurofilament (NF) in nerve roots of Japanese monkeys (Macaca Macacus) was analyzed by two-dimensional electrophoresis combined with immunoblotting. CA was detected as heterogeneous spots of type I and II having the same molecular weight (M(r)) but different isoelectric point (pI), in the range of pH 4.5-5.5. CA had much higher concentrations in soluble fractions of dorsal roots than ventral roots but not in membrane-bound fractions of either root. NF was detected as a single spot at the position of 68 kDa and pI 5.2 in soluble fractions of both roots, however, it was detected in the membrane-bound fractions as heterogeneous spots having different molecular masses and pI in the range of 60-68 kDa and 5.0-5.5, respectively. The presence of heterogeneous CA type I and II at high concentrations in dorsal roots enables us to distinguish the sensory nerves from the motor nerves. Furthermore, the heterogeneity of NF in membrane-bound fractions gives us information for understanding the dynamic assembly and the degradation of NF in nerve roots.