[Characteristic feature in transport of erythrocyte membrane].
This paper gives an overview of recent findings regarding erythrocyte transport. The main transport systems in erythrocyte are Na+, K(+)-ATPase, Ca(2+)-ATPase, anion transport by band 3 protein, water channel and glucose transporter. The kinetics of Na+, K(+)-ATPase had been investigated in detail in several studies and these findings were briefly summarized. The accumulated studies in Ca(2+)-ATPase suggest that the ATPase is also E1/E2 type enzyme. The band 3 protein is most densely distributed protein in the erythrocyte membrane. The anion exchange through band 3 protein is indispensable for CO2 transport from CO2 generating tissues to the lung. The development of molecular biology enabled to discover water channel. The existence of water channel explains the swift movement of water through erythrocyte membrane. The gene for water channel of erythrocyte is designated as AQP1 and is one of gene family, MIP, consisting of 20 genes. The glucose transporter was also identified in the erythrocyte membrane and was named as GLUT1. The transporters involved in Na+, K(+)-cotransport, Na(+)-Li+ countertransport, and Gardos effect remain to be identified.
Department of Clinical Research, National Tohsei Hospital.
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Kojima
D001692:Biological Transport; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D004910:Erythrocyte Membrane / Q000378:metabolism*; D006801:Humans; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase