[Channel-forming protein from a Na, K-ATPase preparation from porcine renal medulla]

Protein inducing formation of the monovalent cation selective channels on bilayer lipid membrane (BLM) was isolated by ethanol extraction from the great subunits of Na+, K+ ATPase or pork kidney microsomes. Conductance of the single channels in the presence of 2 microgram/ml of protein, 0.016 A KC1 and 0.08 M NaCl is equal to 40 p. The membrane potential of a ten-fold potassium ion gradient is close to a theoretical one. Ouabain (5 X 10(-5) M-1 X 10(4) M) inhibits the formation of the channels. KCl (0.03-0.08 M) eliminates the ouabain effect.