ISSN:
1573-5168
Keywords:
gill ATPases
;
branchial plasma membranes
;
Anguilla anguilla
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Branchial activities of Na+,K+-ATPase (ouabain sensitive), Mg2+ ATPase (ouabain insensitive) and kinetic analysis of high and low affinity Ca2+ ATPase were measured inAnguilla anguilla that had been acclimated to demineralized water (DW, Ca 〈 10 μM), freshwater (FW, Ca = 2 mM), and Low calcium freshwater (L-Ca, Ca = 0.9 mM). Na+,K+-ATPase activity decreased while ouabain insensitive activity increased when ambient Ca2+ decreased. Two kinetic forms of Ca2+ ATPase could be resolved in each environmental condition. The stimulation coefficients of both sites or enzymes were not affected by ambient Ca2+ concentrations. The maximal velocity of both the high and the low affinity Ca2+ ATPase was increased when external Ca2+ was decreased during acclimation. The low affinity Ca2+ ATPase and the Mg2+ stimulated enzyme could be a non specific enzyme accepting either Ca2+ or Mg2+. Results are compared with previous results in the literature and in relation to the branchial morphology and ionic exchanges in fish.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00004656
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