𝔖 Bobbio Scriptorium
✦   LIBER   ✦

K+-Phosphatase activity of gill (Na+, K+)-ATPase from the blue crab,Callinectes danae: Low-salinity acclimation and expression of the ?-subunit

✍ Scribed by Masui, D.C. ;Furriel, R.P.M. ;Mantelatto, F.L.M. ;Mcnamara, J.C. ;Leone, F.A.

Publisher
John Wiley and Sons
Year
2005
Tongue
English
Weight
244 KB
Volume
303A
Category
Article
ISSN
1548-8969

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

The kinetic properties of a microsomal gill (Na^+^, K^+^) ATPase from the blue crab, Callinectes danae, acclimated to 15 ‰ salinity for 10 days, were analyzed using the substrate p‐nitrophenylphosphate. The (Na^+^, K^+^)‐ATPase hydrolyzed the substrate obeying Michaelian kinetics at a rate of V=102.9±4.3 U.mg^−1^ with K~0.5~=1.7±0.1 mmol.L^−1^, while stimulation by magnesium (V=93.7±2.3 U.mg^−1^; K~0.5~=1.40±0.03 mmol.L^−1^) and potassium ions (V=94.9±3.5 U.mg^−1^; K~0.5~=2.9±0.1 mmol.L^−1^) was cooperative. K^+^‐phosphatase activity was also stimulated by ammonium ions to a rate of V=106.2±2.2 U. mg^−1^ with K~0.5~=9.8±0.2 mmol.L^−1^, following cooperative kinetics (n~H~=2.9). However, K^+^‐phosphatase activity was not stimulated further by K^+^ plus NH~4~^+^ ions. Sodium ions (K~I~=22.7±1.7 mmol.L^−1^), and orthovanadate (K~I~=28.1±1.4 nmol.L^−1^) completely inhibited PNPPase activity while ouabain inhibition reached almost 75% (K~I~=142.0±7.1 μmol.L^‐1^). Western blotting analysis revealed increased expression of the (Na^+^, K^+^)‐ATPase α‐subunit in crabs acclimated to 15‰ salinity compared to those acclimated to 33‰ salinity. The increase in (Na^+^, K^+^)‐ATPase activity in C. danae gill tissue in response to low‐salinity acclimation apparently derives from the increased expression of the (Na^+^, K)‐ATPase α‐subunit; phosphate‐hydrolyzing enzymes other than (Na^+^, K^+^)‐ATPase are also expressed. These findings allow a better understanding of the kinetic behavior of the enzymes that underlie the osmoregulatory mechanisms of euryhaline crustaceans. J. Exp. Zool. 303A:294–307, 2005. © 2005 Wiley‐Liss, Inc.

📜 SIMILAR VOLUMES

Gill area, permeability and Na+,K+-ATPas
Gill area, permeability and Na+,K+-ATPase activity as a function of size and salinity in the blue crab,Callinectes sapidus
✍ Li, Tiandao ;Roer, Robert ;Vana, Matthew ;Pate, Susan ;Check, Jennifer 📂 Article 📅 2006 🏛 John Wiley and Sons 🌐 English ⚖ 263 KB

Juvenile blue crabs, Callinectes sapidus, extensively utilize oligohaline and freshwater regions of the estuary. With a presumptively larger surface-area-to-body weight ratio, juvenile crabs could experience osmo-and ionoregulatory costs well in excess of that of adults. To test this hypothesis, cra

Osmoregulation and salinity effects on t
Osmoregulation and salinity effects on the expression and activity of Na+,K+-ATPase in the gills of European sea bass,Dicentrarchus labrax (L.)
✍ Jensen, Mette K.; Madsen, Steffen S.; Kristiansen, Karsten 📂 Article 📅 1998 🏛 John Wiley and Sons 🌐 English ⚖ 291 KB 👁 2 views

The European sea bass, Dicentrarchus labrax, tolerates salinities ranging from freshwater (FW) to hypersaline conditions. In two experiments, we analysed changes in plasma ions, muscle water content (MWC), gill Na+,K(+)-ATPase activity, and alpha-subunit mRNA expression during the course of acclimat

Differential induction of branchial carb
Differential induction of branchial carbonic anhydrase and NA+/K+ ATPase activity in the euryhaline crab,Carcinus maenas, in response to low salinity exposure
✍ Henry, Raymond P. ;Garrelts, Elizabeth E. ;McCarty, Melissa M. ;Towle, David W. 📂 Article 📅 2002 🏛 John Wiley and Sons 🌐 English ⚖ 202 KB 👁 1 views

## Abstract The time course of induction of activity of carbonic anhydrase (CA) and Na/K ATPase, two enzymes that are central to osmotic and ionic regulation in the eyryhaline green crab, __Carcinus maenas__, was measured in response to a transfer from 32 to 10 ppt salinity. CA activity was low in