Action of surface-active substances on biological membranes V. Hemolytic,lytic and membrane-perturbing effects of N-lauroyl derivatives of amino acids with aliphatic side chains

Summary The hemolytic action of a number of N-lauroyl derivatives of amino acids with aliphatic side chains on human red cells has been examined. The agents' affinity for the red cell membrane and the mean number of the agent's molecules which, upon binding to an erythrocyte, make it undergo hemolysis have been measured. The relative hydrophobicity of the amino acids' residues under study estimated from the data on the surfactants' micellization has been considered in relation to the literature data. The contributions of the amino acids' side chains to the free energy of the agents' binding to the cell membrane and those to the free energy of the lytic interaction of the agents with the membrane have been evaluated.The effects of the surfactants on the red cell volume and that of N-lauroyl-leucine-Na on the volume of the differently prepared sealed ghosts have been studied.The lyric action of the surfactants has been measured and it is shown that the hemolytic and lytic capacities of an amphiphile appear to be in no relationship with each other.With 2 figures and 3 tables