Interaction of basic polypeptides with phospholipid monolayers

✍ Scribed by I.R. Miller; D. Bach

• Publisher: Elsevier Science
• Year: 1974
• Tongue: English
• Weight: 591 KB
• Volume: 13
• Category: Article
• ISSN: 0009-3084
• DOI: 10.1016/0009-3084(74)90017-6

✦ Synopsis

Adsorption of the polylysine and of the copolypeptides: L-lysine/L-serine and L-lysine/ L-phenylalanine on phospholipid monolayers has been investigated. The charge density of the monolayers was varied by using the negatively charged phosphatidyl serine and the neutral phosphatidyl choline at different ratios. The surface concentrations of the adsorbed polypeptides was determined by measuring the surface radiation of their radioactive label.

The adsorbing capacity of the monolayer surfaces increases with their negative charge, however with respect to polypeptides the surface activity sequence is pL < pLS < pL0. From the dependence of adsorption on the ionic strength it was concluded that it is controlled by three types of interaction: (1) electrostatic attraction to the negatively charged surface; (2) electrostatic repulsion between adsorbed polybases; (3) hydrophobic interactions involving specific structural arrangements. This is true even of the apparently neutral PC monolayer where the fixed phosphate groups form an electrical double layer with the more mobile choline groups which can be interpenetrated by the charged groups of the basic polypeptides.