Molecular activity of Na+/K+-ATPase from different sources is related to the packing of membrane lipids
Ben J. Wu1,2,
Paul L. Else1,2,
Leonard H. Storlien1,2,* and
A. J. Hulbert1,3,
1 Metabolic Research Centre,
2 Department of Biomedical Science and
3 Department of Biological Science, University of Wollongong, Wollongong, NSW 2522, Australia
* Present address: Director of Metabolic Studies, AstraZeneca, R & D Molndal, SE 431 83, Sweden

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Fig. 1. The relationships between average molecular area (per lipid molecule) and surface pressure at 37°C of monolayers of (A) membrane lipids and (B) phospholipids from kidney and brain microsomes of rats (Rattus norvegicus) and cane toads (Bufo marinus). Each symbol represents the mean ± S.E.M. of six determinations.
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Fig. 2. The relationship between the molecular activity of the sodium pump (Na+/K+-ATPase) and the average molecular area per lipid molecule (at a surface pressure of 30 mN m1) of (A) membrane lipids and (B) phospholipids from kidney and brain microsomes of rats (Rattus norvegicus) and cane toads (Bufo marinus). Each symbol represents the mean ± S.E.M. of six determinations. Each inset graph show the relationship for the 24 individual data points.
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Fig. 3. The relationship between the molecular activity of the sodium pump (Na+/K+-ATPase) and the surface pressure of (A) membrane lipids and (B) phospholipids from kidney and brain microsomes of rats (Rattus norvegicus) and cane toads (Bufo marinus). Surface pressures were calculated at an average molecular area (per lipid molecule) of 0.30 nm2 and 0.45 nm2, respectively, for membrane lipids and phospholipids. Each symbol represents the mean ± S.E.M. of six determinations. Each inset graph show the relationship for the 24 individual data points.
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© The Company of Biologists Ltd 2001