{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,2]],"date-time":"2026-05-02T06:41:33Z","timestamp":1777704093761,"version":"3.51.4"},"reference-count":64,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2023,1,3]],"date-time":"2023-01-03T00:00:00Z","timestamp":1672704000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001824","name":"Czech Science Foundation","doi-asserted-by":"publisher","award":["22-07164S"],"award-info":[{"award-number":["22-07164S"]}],"id":[{"id":"10.13039\/501100001824","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>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\u2013Calvet calorimetry in the temperature interval (262\u2013358) 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.<\/jats:p>","DOI":"10.3390\/molecules28010451","type":"journal-article","created":{"date-parts":[[2023,1,4]],"date-time":"2023-01-04T02:54:55Z","timestamp":1672800895000},"page":"451","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":26,"title":["Heat Capacities of L-Cysteine, L-Serine, L-Threonine, L-Lysine, and L-Methionine"],"prefix":"10.3390","volume":"28","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4145-7982","authenticated-orcid":false,"given":"V\u00e1clav","family":"Pokorn\u00fd","sequence":"first","affiliation":[{"name":"Department of Physical Chemistry, University of Chemistry and Technology, Prague, Technick\u00e1 5, CZ-166 28 Prague, Czech Republic"},{"name":"Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovsk\u00e9ho n\u00e1m. 2, CZ-162 06 Prague, Czech Republic"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2839-8546","authenticated-orcid":false,"given":"Vojt\u011bch","family":"\u0160tejfa","sequence":"additional","affiliation":[{"name":"Department of Physical Chemistry, University of Chemistry and Technology, Prague, Technick\u00e1 5, CZ-166 28 Prague, Czech Republic"}]},{"given":"Jakub","family":"Havl\u00edn","sequence":"additional","affiliation":[{"name":"Central Laboratories, University of Chemistry and Technology, Prague, Technick\u00e1 5, CZ-166 28 Prague, Czech Republic"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5707-0670","authenticated-orcid":false,"given":"Michal","family":"Fulem","sequence":"additional","affiliation":[{"name":"Department of Physical Chemistry, University of Chemistry and Technology, Prague, Technick\u00e1 5, CZ-166 28 Prague, Czech Republic"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9048-1036","authenticated-orcid":false,"given":"Kv\u011btoslav","family":"R\u016f\u017ei\u010dka","sequence":"additional","affiliation":[{"name":"Department of Physical Chemistry, University of Chemistry and Technology, Prague, Technick\u00e1 5, CZ-166 28 Prague, Czech Republic"}]}],"member":"1968","published-online":{"date-parts":[[2023,1,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1833","DOI":"10.1021\/acs.jced.9b01086","article-title":"Heat Capacities of L-Alanine, L-Valine, L-Isoleucine, and L-Leucine: Experimental and Computational Study","volume":"65","author":"Fulem","year":"2020","journal-title":"J. Chem. Eng. Data"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"938","DOI":"10.1002\/cphc.202000078","article-title":"Volatility Study of Amino Acids by Knudsen Effusion with QCM Mass Loss Detection","volume":"21","author":"Miranda","year":"2020","journal-title":"ChemPhysChem"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"160","DOI":"10.1007\/s10765-021-02911-z","article-title":"Heat Capacities of l-Arginine, l-Aspartic Acid, l-Glutamic Acid, l-Glutamine, and l-Asparagine","volume":"42","author":"Fulem","year":"2021","journal-title":"Int. J. Thermophys."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Pokorn\u00fd, V., \u0160tejfa, V., Havl\u00edn, J., R\u016f\u017ei\u010dka, K., and Fulem, M. (2021). Heat Capacities of l-Histidine, l-Phenylalanine, l-Proline, l-Tryptophan and l-Tyrosine. Molecules, 26.","DOI":"10.3390\/molecules26144298"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"144504","DOI":"10.1063\/1.5123450","article-title":"Ideal-gas thermodynamic properties of proteinogenic aliphatic amino acids calculated by R1SM approach","volume":"151","author":"Fulem","year":"2019","journal-title":"J. Chem. Phys."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Drauz, K., Grayson, I., Kleemann, A., Krimmer, H.-P., Leuchtenberger, W., and Weckbecker, C. (2000). Amino Acids. Ullmann\u2032s Encyclopedia of Industrial Chemistry, Wiley-VCH Verlag GmbH & Co. KGaA.","DOI":"10.1002\/14356007.a02_057"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"213","DOI":"10.1007\/s12640-017-9814-x","article-title":"L-Serine: A Naturally-Occurring Amino Acid with Therapeutic Potential","volume":"33","author":"Metcalf","year":"2018","journal-title":"Neurotox. Res."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1016\/j.xphs.2017.09.024","article-title":"Coamorphous Active Pharmaceutical Ingredient-Small Molecule Mixtures: Considerations in the Choice of Coformers for Enhancing Dissolution and Oral Bioavailability","volume":"107","author":"Newman","year":"2018","journal-title":"J. Pharm. Sci."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"9385","DOI":"10.1021\/acs.jpcc.5b12420","article-title":"Understanding the Solid-State Hydration Behavior of a Common Amino Acid: Identification, Structural Characterization, and Hydration\/Dehydration Processes of New Hydrate Phases of l-Lysine","volume":"120","author":"Williams","year":"2016","journal-title":"J. Phys. Chem. C"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"3973","DOI":"10.1002\/anie.201411520","article-title":"L-Lysine: Exploiting Powder X-ray Diffraction to Complete the Set of Crystal Structures of the 20 Directly Encoded Proteinogenic Amino Acids","volume":"54","author":"Williams","year":"2015","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Araki, K., and Ozeki, T. (2000). Amino Acids. Kirk-Othmer Encyclopedia of Chemical Technology, John Wiley & Sons, Inc.","DOI":"10.1002\/0471238961.1921182201180111.a01"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"248","DOI":"10.1016\/j.jct.2017.09.022","article-title":"Thermodynamic properties of l-threonine","volume":"116","author":"Lukyanova","year":"2018","journal-title":"J. Chem. Thermodyn."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Weiss, I.M., Muth, C., Drumm, R., and Kirchner, H.O.K. (2018). Thermal decomposition of the amino acids glycine, cysteine, aspartic acid, asparagine, glutamic acid, glutamine, arginine and histidine. BMC Biophys., 11.","DOI":"10.1186\/s13628-018-0042-4"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"44205","DOI":"10.1039\/D0RA08947H","article-title":"Melting properties of amino acids and their solubility in water","volume":"10","author":"Do","year":"2020","journal-title":"RSC Advances"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1016\/0040-6031(90)87002-T","article-title":"Thermal analysis of some \u03b1-amino acids using simultaneous TG-DSC apparatus. The use of dynamic thermogravimetry to study the chemical kinetics of solid state decomposition","volume":"171","author":"Rodante","year":"1990","journal-title":"Thermochim. Acta"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"73","DOI":"10.1016\/0040-6031(88)85219-5","article-title":"DTG and DTA studies on amino acids","volume":"134","author":"Rey","year":"1988","journal-title":"Thermochim. Acta"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"690","DOI":"10.1002\/pat.276","article-title":"Differential scanning calorimetry studies on poly(ethylene glycol) with different molecular weights for thermal energy storage materials","volume":"13","author":"Pielichowski","year":"2002","journal-title":"Polym. Adv. Technol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"871","DOI":"10.1007\/BF01225712","article-title":"Evaluation of thermal decomposition temperatures of amino acids by differential enthalpic analysis","volume":"58","author":"Olafsson","year":"1970","journal-title":"Microchim. Acta"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"307","DOI":"10.1007\/s10973-005-0895-z","article-title":"Relation between chemical structure of amino acids and their thermal decomposition","volume":"82","author":"Wesolowski","year":"2005","journal-title":"J. Therm. Anal. Calorim."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"351","DOI":"10.1016\/0040-6031(96)02827-4","article-title":"Thermal analysis of a series of dipeptides having \u03b1-alanine as the first term. Mutual influence of structures","volume":"284","author":"Rodante","year":"1996","journal-title":"Thermochim. Acta"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1016\/0040-6031(92)87046-D","article-title":"Thermal analysis of different series of dipeptides","volume":"197","author":"Rodante","year":"1992","journal-title":"Thermochim. Acta"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"197","DOI":"10.1016\/0040-6031(92)80018-R","article-title":"Thermal analysis of some \u03b1-amino acids with similar structures","volume":"194","author":"Rodante","year":"1992","journal-title":"Thermochim. Acta"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.tca.2013.04.001","article-title":"The thermochemistry of threonine stereoisomers","volume":"563","author":"Contineanu","year":"2013","journal-title":"Thermochim. Acta"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"o2739","DOI":"10.1107\/S1600536805023688","article-title":"L-Cysteine-I at 30 K","volume":"61","author":"Moggach","year":"2005","journal-title":"Acta Crystallogr. Sect. E"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"2022","DOI":"10.1107\/S0567740875006772","article-title":"A neutron diffraction study of l-cysteine","volume":"31","author":"Kerr","year":"1975","journal-title":"Acta Crystallogr. Sect. B"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"2573","DOI":"10.1107\/S0567740874007618","article-title":"Refinements of the crystal structures of dl-serine and anhydrous l-serine","volume":"30","author":"Kistenmacher","year":"1974","journal-title":"Acta Crystallogr. Sect. B"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"2328","DOI":"10.1021\/ja01162a002","article-title":"The Crystal Structure of Ls-Threonine1","volume":"72","author":"Shoemaker","year":"1950","journal-title":"J. Am. Chem. Soc."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2799","DOI":"10.1107\/S0567740873007569","article-title":"Crystal structures and molecular conformations of l-methionine and l-norleucine","volume":"29","author":"Torii","year":"1973","journal-title":"Acta Crystallogr. Sect. B"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"341","DOI":"10.1107\/S2052252516010472","article-title":"An exceptional series of phase transitions in hydrophobic amino acids with linear side chains","volume":"3","author":"Karen","year":"2016","journal-title":"IUCrJ"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"423","DOI":"10.1007\/s10973-007-8697-0","article-title":"Low-temperature thermodynamic properties of L -cysteine","volume":"93","author":"Paukov","year":"2008","journal-title":"J. Therm. Anal. Calorim."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"132","DOI":"10.1016\/j.vibspec.2012.12.004","article-title":"Using Raman spectroscopy to understand the origin of the phase transition observed in the crystalline sulfur based amino acid l-methionine","volume":"65","author":"Lima","year":"2013","journal-title":"Vib. Spectrosc."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"034501","DOI":"10.1063\/5.0077743","article-title":"Revisiting the phase transition sequence in L-methionine: Description of the disordering mechanism in an essential amino acid","volume":"156","author":"Guinet","year":"2022","journal-title":"J. Chem. Phys."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1016\/0040-6031(84)87046-X","article-title":"DSC-investigations of 22 crystalline neutral aliphatic amino acids in the temperature range 233 to 423 K","volume":"77","author":"Grunenberg","year":"1984","journal-title":"Thermochim. Acta"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"591","DOI":"10.1016\/S0021-9258(18)51724-5","article-title":"Heat capacities and entropies of L-cystine and L-methionine: The transition of L-methionine near 305.5 \u00b0K","volume":"239","author":"Hutchens","year":"1964","journal-title":"J. Biol. Chem."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1016\/0040-6031(81)85184-2","article-title":"Thermodynamics of sulfur compounds II. Thermochemical study of L-cysteine and L-methionine","volume":"43","author":"Sabbah","year":"1981","journal-title":"Thermochim. Acta"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"916","DOI":"10.1002\/poc.2961","article-title":"The enthalpy of formation of methionine revisited","volume":"25","author":"Roux","year":"2012","journal-title":"J. Phys. Org. Chem."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"2124","DOI":"10.1107\/S0567740873006217","article-title":"Structure and conformation of orthorhombic l-cysteine","volume":"29","author":"Kerr","year":"1973","journal-title":"Acta Crystallogr. Sect. B"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1096","DOI":"10.1107\/S0567740868003742","article-title":"The crystal and molecular structure of l-cysteine","volume":"24","author":"Harding","year":"1968","journal-title":"Acta Crystallogr. Sect. B"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"296","DOI":"10.1107\/S0108768105038802","article-title":"High-pressure polymorphism in l-cysteine: The crystal structures of l-cysteine-III and l-cysteine-IV","volume":"62","author":"Moggach","year":"2006","journal-title":"Acta Crystallogr. Sect. B"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1107\/S0108768104031787","article-title":"Effect of pressure on the crystal structure of L-serine-I and the crystal structure of L-serine-II at 5.4 GPa","volume":"61","author":"Moggach","year":"2005","journal-title":"Acta Crystallogr. Sect. B"},{"key":"ref_41","first-page":"61","article-title":"Different behavior of the crystals of L- and DL-serine at high pressure. Transitions in L-serine and the stability of the phase of DL-serine","volume":"404","author":"Kolesnik","year":"2005","journal-title":"Dokl. Akad. Nauk."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"18611","DOI":"10.1021\/acs.jpcc.5b05838","article-title":"Kinetic Control of High-Pressure Solid-State Phase Transitions: A Case Study on l-Serine","volume":"119","author":"Fisch","year":"2015","journal-title":"J. Phys. Chem. C"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"4444","DOI":"10.1039\/C9CE00388F","article-title":"High-pressure polymorphism in l-threonine between ambient pressure and 22 GPa","volume":"21","author":"Giordano","year":"2019","journal-title":"CrystEngComm"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"544","DOI":"10.3891\/acta.chem.scand.50-0544","article-title":"Crystal Structures of Hydrophobic Amino Acids. I. Redeterminations of L-Methionine and L-Valine at 120 K","volume":"50","author":"Dalhus","year":"1996","journal-title":"Acta Chem. Scand."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"1919","DOI":"10.1107\/S0567740870005186","article-title":"The unit cells and space groups of l-methionine, l-[beta]-phenylalanine and dl-tyrosine","volume":"26","author":"Khawas","year":"1970","journal-title":"Acta Crystallogr. Sect. B"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1021\/ja01304a014","article-title":"Thermal Data. III. The Heat Capacities, Entropies and Free Energies of Four Organic Compounds Containing Sulfur","volume":"57","author":"Huffman","year":"1935","journal-title":"J. Am. Chem. Soc."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"4194","DOI":"10.1016\/S0021-9258(18)91154-3","article-title":"Heat capacities from 11 to 305 \u00b0K., entropies, enthalpy, and free-energy formation of L-serine","volume":"239","author":"Hutchens","year":"1964","journal-title":"J. Biol. Chem."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"4807","DOI":"10.1021\/ja01503a013","article-title":"Apparatus and methods for low temperature heat-capacity measurements. Heat capacity of standard benzoic acid","volume":"82","author":"Cole","year":"1960","journal-title":"J. Am. Chem. Soc."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"623","DOI":"10.1006\/jcht.1996.0173","article-title":"Low-temperature heat capacity of 1-bromoperfluorooctane","volume":"29","author":"Varushchenko","year":"1997","journal-title":"J. Chem. Thermodyn."},{"key":"ref_50","unstructured":"Vojt\u00ed\u0161kov\u00e1, O., \u0160tejfa, V., Pokorn\u00fd, V., R\u016f\u017ei\u010dka, K., and Fulem, M. (2022). Heat capacities of selected active pharmaceutical ingredients II. J. Chem. Thermodyn., in preparation."},{"key":"ref_51","doi-asserted-by":"crossref","unstructured":"H\u00f6hne, G., Hemminger, W., and Flammersheim, H.J. (2003). Differential Scanning Calorimetry, Springer.","DOI":"10.1007\/978-3-662-06710-9"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"10077","DOI":"10.1021\/jp9048764","article-title":"Neat liquid consisting of hydrogen-bonded tetramers: Dicyclohexylmethanol","volume":"113","author":"Suzuki","year":"2009","journal-title":"J. Phys. Chem. B"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"369","DOI":"10.1016\/S0011-2275(03)00092-4","article-title":"Critical examination of heat capacity measurements made on a Quantum Design physical property measurement system","volume":"43","author":"Lashley","year":"2003","journal-title":"Cryogenics"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"1107","DOI":"10.1016\/j.jct.2010.04.008","article-title":"Accurate heat capacity measurements on powdered samples using a Quantum Design physical property measurement system","volume":"42","author":"Shi","year":"2010","journal-title":"J. Chem. Thermodyn."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"422","DOI":"10.1007\/s11669-015-0399-x","article-title":"Thermodynamic Properties of Copper","volume":"36","author":"Arblaster","year":"2015","journal-title":"J. Phase Equilib. Diffus."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"2538","DOI":"10.1021\/j100706a022","article-title":"Thermodynamics of Polynuclear Aromatic Molecules.3. Heat Capacities and Enthalpies of Fusion of Anthracene","volume":"74","author":"Goursot","year":"1970","journal-title":"J. Phys. Chem."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"4297","DOI":"10.1021\/ja01350a022","article-title":"Thermal data. I. The heat capacities, entropies and free energies of seven organic compounds containing nitrogen","volume":"54","author":"Huffman","year":"1932","journal-title":"J. Am. Chem. Soc."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"4813","DOI":"10.1021\/ja01503a014","article-title":"Heat Capacities from 11 to 305 \u00b0K. and Entropies of l-Alanine and Glycine","volume":"82","author":"Hutchens","year":"1960","journal-title":"J. Am. Chem. Soc."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"105964","DOI":"10.1016\/j.jct.2019.105964","article-title":"Measurement of low-temperature heat capacity by relaxation technique: Calorimeter performance testing and heat capacity of benzo[b]fluoranthene, benzo[k]fluoranthene, and indeno[1,2,3-cd]pyrene","volume":"142","author":"Mahnel","year":"2020","journal-title":"J. Chem. Thermodyn."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1063\/1.555913","article-title":"Thermodynamic Properties of the NaCl + H2O System l. Thermodynamic Properties of NaCl(cr)","volume":"21","author":"Archer","year":"1992","journal-title":"J. Phys. Chem. Ref. Data"},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"44","DOI":"10.1016\/j.jct.2016.09.041","article-title":"Thermodynamic properties of l-tryptophan","volume":"105","author":"Lukyanova","year":"2017","journal-title":"J. Chem. Thermodyn."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"1840","DOI":"10.1134\/S0036024422090060","article-title":"Thermodynamic Properties of L-Asparagine Monohydrate","volume":"96","author":"Deiko","year":"2022","journal-title":"Russ. J. Phys. Chem. A"},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"1852","DOI":"10.1021\/j100803a027","article-title":"Heat capacities from 11 to 305\u00b0K. and entropies of L-phenylalanine, L-proline, L-tryptophan, and L-tyrosine. Some free energies of formation","volume":"67","author":"Cole","year":"1963","journal-title":"J. Phys. Chem."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"2407","DOI":"10.1016\/S0021-9258(19)67985-8","article-title":"Heat capacities from 11 to 305\u00b0K, entropies and free energies of formation of L-asparagine monohydrate, L-aspartic acid, L-glutamic acid, and L-glutamine","volume":"238","author":"Hutchens","year":"1963","journal-title":"J. Biol. Chem."}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/28\/1\/451\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T17:58:01Z","timestamp":1760119081000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/28\/1\/451"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,1,3]]},"references-count":64,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2023,1]]}},"alternative-id":["molecules28010451"],"URL":"https:\/\/doi.org\/10.3390\/molecules28010451","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,1,3]]}}}