{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,20]],"date-time":"2026-02-20T23:46:17Z","timestamp":1771631177891,"version":"3.50.1"},"reference-count":45,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2024,8,23]],"date-time":"2024-08-23T00:00:00Z","timestamp":1724371200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004271","name":"Sapienza University of Rome","doi-asserted-by":"publisher","award":["RM11715C813C7E84"],"award-info":[{"award-number":["RM11715C813C7E84"]}],"id":[{"id":"10.13039\/501100004271","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004271","name":"Sapienza University of Rome","doi-asserted-by":"publisher","award":["RM1221816A4F3695"],"award-info":[{"award-number":["RM1221816A4F3695"]}],"id":[{"id":"10.13039\/501100004271","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>l-Homocysteine, formed from S-adenosyl methionine following demethylation and adenosine release, accumulates when the methionine recycling pathway and other pathways become impaired, thus leading to hyperhomocysteinemia, a biomarker in cardiovascular diseases, neurological\/psychiatric disorders, and cancer. The partial oxidation of the l-homocysteine thiol group and its decarboxylation on C-alpha lead to the formation of l-homocysteinesulfinic acid (l-HCSA) and homohypotaurine (HHT), respectively. Both compounds are not readily available from commercial suppliers, which hinders the investigation of their biological activities. Herein, the chemical synthesis of l-HCSA, from l-homocystine, was the starting point for establishing the bio-based synthesis of HHT using recombinant Escherichia coli glutamate decarboxylase (EcGadB), an enzyme already successfully employed for the bio-based synthesis of GABA and its phosphinic analog. Prior to HHT synthesis, kcat (33.92 \u00b1 1.07) and KM (38.24 \u00b1 3.45 mM) kinetic constants were determined for l-HCSA on EcGadB. The results of our study show that the EcGadB-mediated synthesis of HHT can be achieved with good yields (i.e., 40% following enzymatic synthesis and column chromatography). Purified HHT was tested in vitro on primary human umbilical vein endothelial cells and rat cardiomyoblasts and compared to the fully oxidized analog, homotaurine (OT, also known as tramiprosate), in widespread pharmaceutical use. The results show that both cell lines display statistically significant recovery from the cytotoxic effects induced by H2O2 in the presence of HHT.<\/jats:p>","DOI":"10.3390\/molecules29173985","type":"journal-article","created":{"date-parts":[[2024,8,23]],"date-time":"2024-08-23T12:38:43Z","timestamp":1724416723000},"page":"3985","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Synthesis and Biological Activity of Homohypotaurine Obtained by the Enzyme-Based Conversion of Homocysteine Sulfinic Acid Using Recombinant Escherichia Coli Glutamate Decarboxylase"],"prefix":"10.3390","volume":"29","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7524-3395","authenticated-orcid":false,"given":"Mario","family":"Fontana","sequence":"first","affiliation":[{"name":"Department of Biochemical Sciences \u201cA. Rossi Fanelli\u201d, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Aysenur","family":"Gunaydin Akyildiz","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Bezmialem Vakif University, 34093 Istanbul, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chiara","family":"D\u2019Alonzo","sequence":"additional","affiliation":[{"name":"Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica 79, 04100 Latina, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0324-1398","authenticated-orcid":false,"given":"Fabio","family":"Giovannercole","sequence":"additional","affiliation":[{"name":"Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica 79, 04100 Latina, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Arianna","family":"Zicchi","sequence":"additional","affiliation":[{"name":"Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica 79, 04100 Latina, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9822-0260","authenticated-orcid":false,"given":"Antonio","family":"Francioso","sequence":"additional","affiliation":[{"name":"Department of Biochemical Sciences \u201cA. Rossi Fanelli\u201d, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3132-6890","authenticated-orcid":false,"given":"Elisabetta","family":"Capuozzo","sequence":"additional","affiliation":[{"name":"Department of Biochemical Sciences \u201cA. Rossi Fanelli\u201d, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3536-9927","authenticated-orcid":false,"given":"Daniela","family":"De Biase","sequence":"additional","affiliation":[{"name":"Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Corso della Repubblica 79, 04100 Latina, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,8,23]]},"reference":[{"key":"ref_1","unstructured":"Devlin, T.M. (2010). Textbook of Biochemistry with Clinical Correlations, John Wiley & Sons. [7th ed.]."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Skovierova, H., Vidomanova, E., Mahmood, S., Sopkova, J., Drgova, A., Cervenova, T., Halasova, E., and Lehotsky, J. (2016). The Molecular and Cellular Effect of Homocysteine Metabolism Imbalance on Human Health. Int. J. Mol. Sci., 17.","DOI":"10.3390\/ijms17101733"},{"key":"ref_3","unstructured":"Pratt, V.M., Scott, S.A., Pirmohamed, M., Esquivel, B., Kattman, B.L., and Malheiro, A.J. (2012). Methylenetetrahydrofolate Reductase Deficiency, Medical Genetics Summaries."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Lajtha, A., Oja, S.S., Schousboe, A., and Saransaari, P. (2007). 7 Sulfur-Containing Amino Acids. Handbook of Neurochemistry and Molecular Neurobiology: Amino Acids and Peptides in the Nervous System, Springer US.","DOI":"10.1007\/978-0-387-30373-4"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"555","DOI":"10.1152\/physrev.00003.2018","article-title":"Homocysteine Modification in Protein Structure\/Function and Human Disease","volume":"99","author":"Jakubowski","year":"2019","journal-title":"Physiol. Rev."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"8294158","DOI":"10.1155\/2020\/8294158","article-title":"Chemistry and Biochemistry of Sulfur Natural Compounds: Key Intermediates of Metabolism and Redox Biology","volume":"2020","author":"Francioso","year":"2020","journal-title":"Oxidative Med. Cell. Longev."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"154051","DOI":"10.1016\/j.metabol.2019.154051","article-title":"High-resolution metabolomics study revealing l-homocysteine sulfinic acid, cysteic acid, and carnitine as novel biomarkers for high acute myocardial infarction risk","volume":"104","author":"Khan","year":"2020","journal-title":"Metab. Clin. Exp."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1109","DOI":"10.1039\/C6MB00732E","article-title":"A metabolomic study on high-risk stroke patients determines low levels of serum lysine metabolites: A retrospective cohort study","volume":"13","author":"Lee","year":"2017","journal-title":"Mol. Biosyst."},{"key":"ref_9","first-page":"299","article-title":"Evaluation of salivary metabolomics in oral leukoplakia and oral squamous cell carcinoma","volume":"48","author":"Sridharan","year":"2019","journal-title":"J. Oral Pathol. Med. Off. Publ. Int. Assoc. Oral Pathol. Am. Acad. Oral Pathol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/0165-6147(90)90038-A","article-title":"Structure-activity relationships in the development of excitatory amino acid receptor agonists and competitive antagonists","volume":"11","author":"Watkins","year":"1990","journal-title":"Trends Pharmacol. Sci."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1186\/s13195-020-00663-w","article-title":"Aducanumab, gantenerumab, BAN2401, and ALZ-801-the first wave of amyloid-targeting drugs for Alzheimer\u2019s disease with potential for near term approval","volume":"12","author":"Tolar","year":"2020","journal-title":"Alzheimers Res. Ther."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Martorana, A., Di Lorenzo, F., Manenti, G., Semprini, R., and Koch, G. (2014). Homotaurine induces measurable changes of short latency afferent inhibition in a group of mild cognitive impairment individuals. Front. Aging Neurosci., 6.","DOI":"10.3389\/fnagi.2014.00254"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Meera, P., Uusi-Oukari, M., Lipshutz, G.S., and Wallner, M. (2023). GABA(A) receptors as plausible molecular targets and mediators for taurine and homotaurine actions. Front. Pharmacol., 14.","DOI":"10.3389\/fphar.2023.1271203"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1797","DOI":"10.1111\/j.1471-4159.1973.tb00299.x","article-title":"Decarboxylation of DL-homocysteinesulphinic acid (2-amino 4-sulphinobutyric acid) in rat brain","volume":"20","year":"1973","journal-title":"J. Neurochem."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1016\/0003-2697(73)90474-0","article-title":"Synthesis of homohypotaurine (3-aminopropansulfinic acid) and homothiotaurine (3-aminopropanthiosulfonic acid)","volume":"51","author":"Rinaldi","year":"1973","journal-title":"Anal. Biochem."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Francioso, A., Dupr\u00e9, S., and Fontana, M. (2022). Chemistry of Outlandish Natural Products Belonging to Sulfur Metabolism: Unrevealed Green Syntheses and Separation Strategies from the Cavallini\u2019s Old School. Separations, 9.","DOI":"10.3390\/separations9020045"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"569","DOI":"10.1111\/j.1432-1033.1969.tb00726.x","article-title":"A new sulfinic amino acid: Homohypotaureine (3-aminopropanesulfinic acid). Isolation, determination and chromatographic behaviour compared with sulfinic and sulfonic derivatives of cysteine and homocysteine","volume":"10","year":"1969","journal-title":"Eur. J. Biochem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"4027","DOI":"10.1093\/emboj\/cdg403","article-title":"Crystal structure and functional analysis of Escherichia coli glutamate decarboxylase","volume":"22","author":"Capitani","year":"2003","journal-title":"EMBO J."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"770","DOI":"10.1111\/mmi.12020","article-title":"Glutamate decarboxylase-dependent acid resistance in orally acquired bacteria: Function, distribution and biomedical implications of the gadBC operon","volume":"86","author":"Pennacchietti","year":"2012","journal-title":"Mol. Microbiol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"578","DOI":"10.1128\/AEM.02928-14","article-title":"Glutamate decarboxylase-dependent acid resistance in Brucella spp.: Distribution and contribution to fitness under extremely acidic conditions","volume":"81","author":"Damiano","year":"2015","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1091","DOI":"10.1111\/1574-6976.12076","article-title":"Coping with low pH: Molecular strategies in neutralophilic bacteria","volume":"38","author":"Lund","year":"2014","journal-title":"FEMS Microbiol. Rev."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Lakicevic, B.Z., Den Besten, H.M.W., and De Biase, D. (2021). Landscape of Stress Response and Virulence Genes Among Listeria monocytogenes Strains. Front. Microbiol., 12.","DOI":"10.3389\/fmicb.2021.738470"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"2643","DOI":"10.1038\/sj.emboj.7601107","article-title":"Escherichia coli acid resistance: pH-sensing, activation by chloride and autoinhibition in GadB","volume":"25","author":"Gut","year":"2006","journal-title":"EMBO J."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"31587","DOI":"10.1074\/jbc.M109.049577","article-title":"Mutation of His465 alters the pH-dependent spectroscopic properties of Escherichia coli glutamate decarboxylase and broadens the range of its activity toward more alkaline pH","volume":"284","author":"Pennacchietti","year":"2009","journal-title":"J. Biol. Chem."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1562","DOI":"10.1039\/b913741f","article-title":"The application of glutamic acid \u03b1-decarboxylase for the valorization of glutamic acid","volume":"11","author":"Lammens","year":"2009","journal-title":"Green Chem."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1038\/s42004-020-00368-z","article-title":"Enzymatic kinetic resolution of desmethylphosphinothricin indicates that phosphinic group is a bioisostere of carboxyl group","volume":"3","author":"Cappadocio","year":"2020","journal-title":"Commun. Chem."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1304","DOI":"10.1021\/bi00757a029","article-title":"Glutamate decarboxylase. Substrate specificity and inhibition by carboxylic acids","volume":"11","author":"Fonda","year":"1972","journal-title":"Biochemistry"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"209","DOI":"10.1016\/j.fob.2015.03.006","article-title":"Biochemical and spectroscopic properties of Brucella microti glutamate decarboxylase, a key component of the glutamate-dependent acid resistance system","volume":"5","author":"Grassini","year":"2015","journal-title":"FEBS Open Bio"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"553","DOI":"10.1016\/S0300-9084(71)80173-6","article-title":"[Bacterial L-glutamate decarboxylases: Their action on L homocysteinesulfinic acid and L-homocysteic acid]","volume":"53","author":"Charton","year":"1971","journal-title":"Biochimie"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"236","DOI":"10.1016\/0003-2697(72)90023-1","article-title":"Synthesis of homocysteinesulfinic acid","volume":"45","author":"Luchi","year":"1972","journal-title":"Anal. Biochem."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Roberts, P.J., Storm-Mathisen, J., and Bradford, H.F. (1986). Identification of Pathways for Acidic Amino Acid Transmitters and Search for New Candidates: Sulphur-containing Amino Acids. Excitatory Amino Acids, Palgrave Macmillan UK.","DOI":"10.1007\/978-1-349-08479-1"},{"key":"ref_32","first-page":"930","article-title":"[Metabolism of L-homocysteinesulfinic acid in higher animals]","volume":"262","year":"1966","journal-title":"Comptes Rendus Hebd. Seances L\u2019academie Sci. Ser. D Sci. Nat."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"547","DOI":"10.1016\/0197-0186(90)90042-R","article-title":"Displacement of [(3)H]GABA binding to bovine brain receptors by sulfur-containing analogues","volume":"17","author":"Costa","year":"1990","journal-title":"Neurochem. Int."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Negri, S., Scolari, F., Vismara, M., Brunetti, V., Faris, P., Terribile, G., Sancini, G., Berra-Romani, R., and Moccia, F. (2022). GABAA and GABAB Receptors Mediate GABA-Induced Intracellular Ca2+ Signals in Human Brain Microvascular Endothelial Cells. Cells, 11.","DOI":"10.3390\/cells11233860"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"68","DOI":"10.1016\/j.cbpc.2018.11.018","article-title":"A novel mechanism of Gamma-aminobutyric acid (GABA) protecting human umbilical vein endothelial cells (HUVECs) against H(2)O(2)-induced oxidative injury","volume":"217","author":"Zhu","year":"2019","journal-title":"Comp. Biochem. Physiol. Toxicol. Pharmacol. CBP"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"430","DOI":"10.1006\/prep.1996.0121","article-title":"Isolation, overexpression, and biochemical characterization of the two isoforms of glutamic acid decarboxylase from Escherichia coli","volume":"8","author":"Tramonti","year":"1996","journal-title":"Protein Expr. Purif."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1016\/j.jphs.2023.11.003","article-title":"Identification of a novel enzyme and the regulation of key enzymes in mammalian taurine synthesis","volume":"154","author":"Miyazaki","year":"2024","journal-title":"J. Pharmacol. Sci."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"573","DOI":"10.1007\/978-94-024-1079-2_45","article-title":"The Interaction of Hypotaurine and Other Sulfinates with Reactive Oxygen and Nitrogen Species: A Survey of Reaction Mechanisms","volume":"975","author":"Pecci","year":"2017","journal-title":"Adv. Exp. Med. Biol."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Ram\u00edrez-Guerrero, S., Guardo-Maya, S., Medina-Rinc\u00f3n, G.J., Orrego-Gonz\u00e1lez, E.E., Cabezas-P\u00e9rez, R., and Gonz\u00e1lez-Reyes, R.E. (2022). Taurine and Astrocytes: A Homeostatic and Neuroprotective Relationship. Front. Mol. Neurosci., 15.","DOI":"10.3389\/fnmol.2022.937789"},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Kim, B., and Jung, J. (2024). Metabolomic Approach to Identify Potential Biomarkers in KRAS-Mutant Pancreatic Cancer Cells. Biomedicines, 12.","DOI":"10.3390\/biomedicines12040865"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1551","DOI":"10.1038\/sj.bjp.0701533","article-title":"Analogues of gamma-aminobutyric acid (GABA) and trans-4-aminocrotonic acid (TACA) substituted in the 2 position as GABAC receptor antagonists","volume":"122","author":"Chebib","year":"1997","journal-title":"Br. J. Pharmacol."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"2228","DOI":"10.1021\/jacsau.4c00182","article-title":"CoVAMPnet: Comparative Markov State Analysis for Studying Effects of Drug Candidates on Disordered Biomolecules","volume":"4","author":"Marques","year":"2024","journal-title":"JACS Au"},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"Dadi, P., Pauling, C.W., Shrivastava, A., and Shah, D.D. (2024). Synthesis of versatile neuromodulatory molecules by a gut microbial glutamate decarboxylase. Biorxiv Prepr. Serv. Biol.","DOI":"10.1101\/2024.03.02.583032"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1111\/j.1432-1033.1974.tb03346.x","article-title":"Enzymatic and chemical synthesis of 3-sulfinopropionic acid, an analog of succinic acid","volume":"42","year":"1974","journal-title":"Eur. J. Biochem."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1016\/0022-1759(83)90303-4","article-title":"Rapid colorimetric assay for cellular growth and survival: Application to proliferation and cytotoxicity assays","volume":"65","author":"Mosmann","year":"1983","journal-title":"J. Immunol. Methods"}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/29\/17\/3985\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T15:42:04Z","timestamp":1760110924000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/29\/17\/3985"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,8,23]]},"references-count":45,"journal-issue":{"issue":"17","published-online":{"date-parts":[[2024,9]]}},"alternative-id":["molecules29173985"],"URL":"https:\/\/doi.org\/10.3390\/molecules29173985","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,8,23]]}}}