High affinity, Ca2+ specific ATPase and Na+K(+)-ATPase in the gills of a supralittoral crab Leptograpsus variegatus.
1. The gills of Leptograpsus variegatus contain a high-affinity, Ca(2+)-activated ATPase, probably located in the basolateral plasma membrane of the gill epithelia. 2. The affinity of the ATPase for Ca2+ is in the micromolar concentration range (6-35 mumol/l). 3. The specific activity of the enzyme did not change during the moult cycle. The ATPase probably does not contribute substantially to increased calcium influx from the medium during the post moult period. 4. The enzyme is believed to function as a selective extrusion mechanism involved in the maintenance of a low cytosolic Ca2+ level in the epithelial cells.
School of Biological Science, University of New South Wales, Kensington, Australia.
M A
MA
Morris
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Greenaway
D000818:Animals; D001693:Biological Transport, Active; D003386:Brachyura / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D005880:Gills / Q000378:metabolism; D007700:Kinetics; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium