Crystal structures together with enthalpies and temperatures of fusion of two substituted amino acids, N-acetylsarcosinamide (NASarA) and N-acetyl-L-isoleucinamide (NAIA), were determined by single crystal X-ray analysis and differential scanning calorimetry, respectively. The results were compared with those of some analogous amino acid derivatives previously studied. The detailed knowledge of crystallographic parameters is undoubtedly useful for discussing the thermodynamic results and rationalizing the fusion behaviour, owing to the rather poor knowledge of the molecular interactions occurring in the melt.
Authors:G. Barone, S. Capasso, P. Del Vecchio, C. De Sena, D. Fessas, C. Giancola, G. Graziano, and P. Tramonti
In a previous paper, we report a preliminary DSC study on bovine (BSA) and human (HSA) serum albumins. However, at accurate
HPLC analysis the commercial proteins show three peaks: Fraction V-I, probably globulins (as declared by the producers), Fraction
V-II (about 15–18% of the product) and Fraction V-III that represents pure BSA or HSA. A hypothesis is that the Fraction II
is a covalent dimer, or trimer or a mixture of both, generated during the scalf-life of the commercial product.
Denaturation enthalpies of the purified Fraction V-III and Fraction V-II of BSA, have been determined calorimetrically, at
changing thepH, and the results of both compared with those obtained on the untreated protein. Few calorimetric experiments have been also
carried on a BSA monomer derivative with sulphidril group protected. Computer program have been developed for the deconvolution
of exo- and endothermic effects and for the analysis of thermal denaturation profiles.