EFFECT OF DENERVATION ON THE (NA+,K+)ATPASE ACTIVITY OF ELECTROPHORUS-ELECTRICUS (L) ELECTROCYTE

1. The effect of denervation on membrane-bound (Na+, K+)ATPase activity from the non-innervated (fraction P2) and innervated (fraction P3) membrane faces of Electrophorus electricus (L.) electrocyte is described. 2. After 20 days denervation both fractions presented a decreased (Na+, K+)Mg2+-dependent ATPase activity as compared with the normal electrocyte fractions. 3. When submitted to a discontinuous sucrose gradient, normal P2 membrane fraction exhibits a bimodal distribution of the enzyme which upon denervation changes to an unimodal distribution. P3 fraction showed a similar but less evident change of the enzyme distribution. 4. Sialic acid, which is described as a constituent of the enzyme beta-subunit, also showed a higher decrease (26.51%) in denervated P2 fraction as compared with P3 denervated membrane fraction (9%).