AJP - Regulatory, Integrative and Comparative Physiology, Vol 238, Issue 3 251-R259, Copyright © 1980 by American Physiological Society
Cl--HCO3--ATPase in gills of the rainbow trout: evidence for its microsomal localization
M. Bornancin, G. de Renzis and R. Naon
The intracellular localization of a Cl--HCO3--ATPase, which is inhibited by
SCN-, was studied in the gills of the rainbow trout, Salmo gairdneri. This
activity can be measured in the absence of contamination by mitochondria
(i.e., in the absence of succinate dehydrogenase or cytochrome c oxidase
activities). The distribution of the 5'-nucleotidase and of the ATPase
stimulated by Cl- and HCO3- after sucrose density gradient centrifugation
of the microsomal fraction was compared. Because those activities cannot be
separated, it is postulated that the anion-stimulated ATPase is located in
the plasma membrane. The activation of this microsomal anion ATPase by
chloride has been studied extensively. The possible role of the
Cl--HCO3--ATPase of trout gills in the Cl-/HCO3- exchange and in the
regulation of the internal acid-base balance is discussed.
