Adsorption of pepsin in octadecylamine matrix at air–water interface

Incorporation of pepsin within zwitterionic, anionic, and cationic lipid monolayers: A comparative study

“…This initial lag phase is the diffusion-limited regime, a significant characteristic of protein/enzyme adsorption process, where the interface is lacking sufficient quantity of protein/ enzyme for noticeable change in p. Thus, the lag time is the time required for attaining the minimum monolayer coverage for an effectual and measurable surface pressure. [23][24][25] After the lag phase, an initial faster increase followed by a slower increase of p was observed. The first step is the diffusion of the molecule to just below the interface after which the adsorption is in effect at the air/water interface.…”

“…The details of experimental processes were similar with our previous experiment described elsewhere. 23,24 For preparation of pure PEP film, a known amount of aqueous solution of PEP of concentration 1 mg/mL was spread on the water subphase by a micro syringe. A similar technique was used for the preparation of lipid monolayer where chloroform solution of lipid (1 mM) was spread on the water subphase by a micro syringe.…”

“…p-t measurements of pure PEP at various concentrations of PEP along with the association behavior of PEP with ODA Langmuir monolayer. 23,24 The C PEP dependent p-t curves showed that there were initial lag times (t lag ) where t lag values remained near zero. This initial lag phase is the diffusion-limited regime, a significant characteristic of protein/enzyme adsorption process, where the interface is lacking sufficient quantity of protein/ enzyme for noticeable change in p. Thus, the lag time is the time required for attaining the minimum monolayer coverage for an effectual and measurable surface pressure.…”

“…In our recent communications, 23 the interaction of a soluble surface-active enzyme, the pepsin (PEP) with cationic octadecylamine (ODA) is studied at air/water interface. This study creates a question about the behavior and the possible mechanism of association of PEP in zwitterionic and in anionic monolayer.…”

Adsorption of a water soluble cationic dye into a cationic Langmuir monolayer

“…In a recent work the adsorption of DNA into the preformed Langmuir monolayer of cationic surfactant ODA at the air-water interface has been studied [3]. The incorporation of water soluble anionic surface active enzyme Pepsin (PEP) within an insoluble cationic ODA Langmuir monolayer was investigated by changing various parameters [9]. The most important works in this respect are the adsorption of various anionic and cationic molecules into the zwitterionic lipid monolayer of DPPC.…”