A possible glass transition for poly(l-methionine) and poly(l-serine)

Vibrational heat capacity of silver carp collagen

The study of the experimental and calculated heat capacity, C_p of fish collagen (silver carp) with contents of several additive components was presented. The experimental low-temperature heat capacity was measured in the temperature range of 1.85 to 302.8 K using a Quantum Design Physical Property Measurement System (PPMS) and the higher temperature C_p from 223.15 K to 382.15 K by Differential Scanning Calorimetry (DSC) method. For an interpretation of the experimental, low-temperature data, the vibrational heat capacity of the pure silver carp collagen was calculated based on the contribution of a sum of the vibrational heat capacity of 4248 amino acids. The vibrational heat capacity for each amino acids was taken from Advanced Thermal Analysis System (ATHAS) Data Bank for individual poly (amino acid) residues based on their group and skeletal vibrational spectra. Comparing of the experimental heat capacity of the collagen with additive components and the calculated vibrational heat capacity of the pure silver carp collagen shows that the differences range from around 10% at 100 K to 14% at 300 K temperature. Such thermal analysis can provide information about the contribution to C_p of unknown components or impurities in the investigated system.

Water vapor sorption by peptides, proteins and their formulations

The interactions of pharmaceutical peptides, proteins and their formulations with environmental water vapor are reviewed. Particular attention is paid to the importance of the physical structure and chemical diversity of peptides and proteins, and comparisons are made with the mechanisms of water vapor sorption by synthetic macromolecular systems. The influences of formulation processes and additives are also considered and suggestions made for future areas of research.