Mixed monolayers binding isotherm

In another study by Kunitake, the amphiphile 45 was used to bind dipeptides at the air-water interface [75]. Using mixed monolayers of45 and a dioctadecyl glycylglycinamide amphiphile, a Langmuir isotherm for the binding of Gly-Leu was produced. The result was a cooperative binding event between the two... 

The binding of cytochrome c (Cyt c) to a monolayer of Chi a is studied using surface pressure (77) vs area (A), surfaee potential (dF) vs area (A) and ( C)Cyt c surface-concentration (F) vs area (A) isotherms [62]. The protein is incorporated into a Chi a monolayer compressed at a surface pressure of 20 mN/m. On expansion, the quantity of Cyt c incorporated into the monolayer gradually increases. This is supported by the increase of 77 and AV after the protein is being injected in the subphase. The subsequent cycles of compression and expansions result in similar isotherms which are distinct from that measured at the first expansion. In addition to the latter observation, the surface radioactivity of ( C)Cyt c indicates the irreversibility of protein incorporation into the Chi a mono-layer. In fact, the surface properties of the binary film are completely different from those of either pure compounds. As a result, calculated values of AV for mixed monolayers assuming additivity deviate from experiment. 

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