IMMUNOLOCALIZATION OF PROTON-ATPASE IN THE GILLS OF THE ELASMOBRANCH,SQUALUS-ACANTHIAS

Proton-ATPase was localized to mitochondria-rich cells in the interlam ellar region of the gills of the elasmobranch, Squalus acanthias. Loca lization was accomplished using a polyclonal antibody specific for the 70 kDa subunit of the (V-type) proton-ATPase as confirmed by Western blot analysis. In addition, significant levels of N-ethymaleimide sens itive ATPase activity (0.116 +/- 0.026 mu mol P-i . mg(-1) protein . h (-1)) were also measured in crude gill membrane preparations. These da ta provide, for the first time, direct evidence of the localization of elements possibly involved in branchial acid-base (or ionic) regulati on in elasmobranchs. (C) 1997 Wiley-Liss, Inc.