Effect of aqueous subphase exchange on the monolayer characteristics of valinomycin

✍ Scribed by S. Yu. Zaitsev; U. Kalmer; D. Mo¨bius

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 508 KB
• Volume: 94
• Category: Article
• ISSN: 0927-7757
• DOI: 10.1016/0927-7757(94)02968-7

✦ Synopsis

A special construction was built for the measurement of monolayer characteristics of surface-active substances during aqueous subphase exchange. These measurements are important for the determination of the specificity and reversibility of the interactions between amphiphiles and various compounds dissolved in the aqueous subphase. No changes in the surface pressure-molecular area isotherms were observed during dilution of the salt subphase underneath monolayers of fatty alcohols, such as octadecanol (i.e. no interaction). Small reversible changes found under the same conditions for monolayers of various fatty acids (for example docosanoic acid) are considered to be non-specific interactions. Two additional pronounced states (II and III) of valinomycin monolayers were observed in the presence of K + , compared with Na + that correlates with the strong complexation between valinomycin and these cations in bulk (specific interaction). These changes in the monolayers of valinomycin and fatty acids are completely reversible, in contrast with the irreversible changes for catalase monolayers during aqueous subphase exchange.