Interaction of cysteine and its derivatives with monolayers of dipalmitoylphosphatidylcholine

DIAZ,SONIA BEATRIZ; ARIAS, JUAN MARCELO; DUPUY, FERNANDO GABRIEL; BEN ALTABEF, AIDA

COLLOIDS AND SURFACES B-BIOINTERFACES

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2019

0927-7765

Molecular interactions between L-cysteine (Cys) and its esterderivatives (Cysx); L-cysteine ethyl ester (CE), L-cysteine methyl ester (CM)and N-acetyl L-cysteine (NAC) with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine(DPPC) monolayers were investigated using Langmuir film balance technique. Theeffect of charge on monolayers made of cysteine and three ester derivativeswith DPPC was investigated by working with un-buffered and buffered subphases.Also, the effects of cysteine derivatives interaction with DPPC monolayers werestudied measuring the change in the surface tension upon aminoacid injection inthe subphase whilst keeping lipid molecular density and lateral packingcontrolled.Cysteine and its ester derivatives showed interfacial activity reducingthe air/water surface tension (pi) by 4 mN·m-1. However, ester derivatives were able to insert into preformedDPPC monolayers at much higher surface pressures (Dp), indicating a preferentialinteraction of Cysx with DPPC.The results indicate that, although the different derivatives ofcysteine presented low surface activity, they were able to favourably interactwith DPPC monolayers. Also, compression isotherms experiments in binarymixtures indicate that the more surface active compounds stabilized the gelphase of DPPC. The charge on cysteine and its derivatives did not increase theobserved effects.