Heat capacities of L-cysteine, L-serine, L-threonine, L-lysine, and L-methionine

0566955 - ÚMCH 2024 RIV CH eng J - Journal Article
Pokorný, Václav - Štejfa, V. - Havlín, J. - Fulem, M. - Růžička, K.
Heat capacities of L-cysteine, L-serine, L-threonine, L-lysine, and L-methionine.
Molecules. Roč. 28, č. 1 (2023), č. článku 451. E-ISSN 1420-3049
Institutional support: RVO:61389013
Keywords : L-cysteine * L-serine * L-threonine
OECD category: Polymer science
Impact factor: 4.6, year: 2022
Method of publishing: Open access
https://www.mdpi.com/1420-3049/28/1/451

In an effort to establish reliable thermodynamic data for amino acids, heat capacity and phase behavior are reported for L-cysteine (CAS RN: 52-90-4), L-serine (CAS RN: 56-45-1), L-threonine (CAS RN: 72-19-5), L-lysine (CAS RN: 56-87-1), and L-methionine (CAS RN: 63-68-3). Prior to heat capacity measurements, initial crystal structures were identified by X-ray powder diffraction, followed by a thorough investigation of the polymorphic behavior using differential scanning calorimetry in the temperature range from 183 K to the decomposition temperature determined by thermogravimetric analysis. Crystal heat capacities of all five amino acids were measured by Tian–Calvet calorimetry in the temperature interval (262–358) K and by power compensation DSC in the temperature interval from 215 K to over 420 K. Experimental values of this work were compared and combined with the literature data obtained with adiabatic calorimetry. Low-temperature heat capacities of L-threonine and L-lysine, for which no or limited literature data was available, were measured using the relaxation (heat pulse) calorimetry. As a result, reference heat capacities and thermodynamic functions for the crystalline phase from near 0 K to over 420 K were developed.
Permanent Link: https://hdl.handle.net/11104/0338227