THERMODYNAMICS OF DIPEPTIDES IN WATER .5. CALORIMETRIC DETERMINATION OF ENTHALPY CHANGE VALUES RELATED TO PROTON-TRANSFER PROCESSES OF A SERIES OF DIPEPTIDES IN WATER

We have made calorimetric determination of enthalpy change values rela ted to proton dissociation processes (for a series of dipeptides havin g alpha-alanine as first common term) of the free alpha-amino groups b elonging to the amino terminal residue (N-terminal) and of the free al pha-carboxyl groups belonging to the carboxyl terminal residue (C-term inal). These values were subsequently compared with those related to p roton dissociation processes of the corresponding groups of alanyl-ala nine and of the individual free alpha-amino acids. The results were in terpreted in terms of reciprocal influence of the components of the di peptides. (C) 1997 Elsevier Science B.V.