, Volume 57, Issue 5, pp 621-627
Date: 29 Dec 2012

Isolation and purification of human blood plasma proteins able to form potassium channels in artificial bilayer lipid membrane

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Abstract

A protein fraction able to induce K+-selective transport across a bilayer lipid membrane was isolated from human blood plasma with the use of the detergent- and proteolytic enzyme-free method developed in our laboratory. After addition of the studied sample to the artificial membrane in the presence of 100 mM KCl, a discrete current change was observed. No channel activity was recorded in the presence of calcium and sodium ions. Channel-forming activity of the fraction was observed only in the presence of K+. Using a threefold gradient of KCl in the presence of studied proteins, a potassium-selective potential balanced by voltage of −29 mV was registered. This value is very close to the theoretical Nernst potential in this case. This means that the examined ion channel is cation-selective. According to the data obtained with MS-MALDI-TOF/TOF and NCBI database, three protein components were identified in the isolated sample.

Original Russian Text © N.I. Venediktova, K.V. Kuznetsov, E.N. Gritsenko, G.P. Gulidova, G.D. Mironova, 2012, published in Biofizika, 2012, Vol. 57, No. 5, pp. 805–812.