Biochemistry of Na,K-ATPase.
The Na,K-ATPase or sodium pump carries out the coupled extrusion and uptake of Na and K ions across the plasma membranes of cells of most higher eukaryotes. It is a member of the P-type ATPase superfamily. This heterodimeric integral membrane protein is composed of a 100-kDa alpha-subunit with ten transmembrane segments and a heavily glycosylated beta subunit of about 55 kDa, which is a type II membrane protein. Current ideas on how the protein achieves active transport are based on a fusion of results of transport physiology, protein chemistry, and heterologous expression of mutant proteins. Recently acquired high resolution structural information provides an important new avenue for a more complete understanding of this protein. In this review, the current status of knowledge of Na,K-ATPase is discussed, and areas where there is still considerable uncertainty are highlighted.
Kaplan
Jack H
JH
Department of Biochemistry and Molecular Biology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97201, USA. kaplanj@ohsu.edu
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D001693:Biological Transport, Active / Q000502:physiology*; D000252:Calcium-Transporting ATPases / Q000737:chemistry / Q000378:metabolism; D004070:Digitalis / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry* / Q000378:metabolism*
D021122:Protein Subunits; D000255:Adenosine Triphosphate; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase