{"title":"铝(III)离子与l -组氨酸或l -酪氨酸的溶液平衡。","authors":"Predrag Djurdjevic, Ratomir Jelic, Dragana Dzajevic, Mirjana Cvijovic","doi":"10.1155/MBD.2002.235","DOIUrl":null,"url":null,"abstract":"<p><p>Toxic effects due to high aluminum body loads were observed in a number of conditions following ingestion of Al-containing antacids. Bio-availability of aluminum depends not only on the solubility of the ingested salt but also on the physico-chemical properties of the soluble Al complexes formed in body fluids. Amino acids may, upon interaction with Al-salts, form absorbable Al-complexes. Hence, complex formation equilibria between Al(3+) and either, L- histidine or L-tyrosine were studied by glass electrode potentiometric (0.1 mol/L LiCl ionic medium, 298 K), proton NMR and uv spectrophotometric measurements. Non linear least squares treatment of the potentiometric data indicates that in the concentration ranges: 0.5</=C(A1)</=2.0 ; 1.0</=C(His)</=10.0; 2.5</=PH</=6.5, in Al(3+) + His solutions, the following complexes (with log overall stability constants given in parenthesis) are formed: Al(HHis)(3+)(12.21+/-0.08); Al(His)(2+), (7.25+/-0.08); and Al(HHis)His(2+), (20.3+/-0.1). In Al(3+) + Tyr solutions in the concentration range 1.0</=C(Tyr)</=3.0 mmol/L and ligand to metal concentration ratio from 2:1 to 3:1, in the pH interval from 3.0 to 6.5 the formation of the following complexes was detected: Al(HTyr)(2+), (12.72+/-0.09); Al(Tyr)(2+), (10.16+/-0.03) and Al(OH)(2)Tyr , (2.70+/-0.05). Proton NMR data indicate that in Al(His)(2+) complex histidine acts as a monodentate ligand but its bidentate coordination is possible with carboxylate oxygen and imidazole 1-nitrogen as donors. In Al(HTyr)(3+) complex tyrosine is a monodentate ligand with carboxylate oxygen as donor. The mechanism of the formation of complexes in solution is discussed as well as their possible role in aluminum toxicity.</p>","PeriodicalId":18452,"journal":{"name":"Metal-Based Drugs","volume":"8 5","pages":"235-48"},"PeriodicalIF":0.0000,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/MBD.2002.235","citationCount":"7","resultStr":"{\"title\":\"Solution Equilibria between Aluminum(III) Ion and L-histidine or L-tyrosine.\",\"authors\":\"Predrag Djurdjevic, Ratomir Jelic, Dragana Dzajevic, Mirjana Cvijovic\",\"doi\":\"10.1155/MBD.2002.235\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Toxic effects due to high aluminum body loads were observed in a number of conditions following ingestion of Al-containing antacids. Bio-availability of aluminum depends not only on the solubility of the ingested salt but also on the physico-chemical properties of the soluble Al complexes formed in body fluids. Amino acids may, upon interaction with Al-salts, form absorbable Al-complexes. Hence, complex formation equilibria between Al(3+) and either, L- histidine or L-tyrosine were studied by glass electrode potentiometric (0.1 mol/L LiCl ionic medium, 298 K), proton NMR and uv spectrophotometric measurements. Non linear least squares treatment of the potentiometric data indicates that in the concentration ranges: 0.5</=C(A1)</=2.0 ; 1.0</=C(His)</=10.0; 2.5</=PH</=6.5, in Al(3+) + His solutions, the following complexes (with log overall stability constants given in parenthesis) are formed: Al(HHis)(3+)(12.21+/-0.08); Al(His)(2+), (7.25+/-0.08); and Al(HHis)His(2+), (20.3+/-0.1). In Al(3+) + Tyr solutions in the concentration range 1.0</=C(Tyr)</=3.0 mmol/L and ligand to metal concentration ratio from 2:1 to 3:1, in the pH interval from 3.0 to 6.5 the formation of the following complexes was detected: Al(HTyr)(2+), (12.72+/-0.09); Al(Tyr)(2+), (10.16+/-0.03) and Al(OH)(2)Tyr , (2.70+/-0.05). Proton NMR data indicate that in Al(His)(2+) complex histidine acts as a monodentate ligand but its bidentate coordination is possible with carboxylate oxygen and imidazole 1-nitrogen as donors. In Al(HTyr)(3+) complex tyrosine is a monodentate ligand with carboxylate oxygen as donor. The mechanism of the formation of complexes in solution is discussed as well as their possible role in aluminum toxicity.</p>\",\"PeriodicalId\":18452,\"journal\":{\"name\":\"Metal-Based Drugs\",\"volume\":\"8 5\",\"pages\":\"235-48\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2002-01-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://sci-hub-pdf.com/10.1155/MBD.2002.235\",\"citationCount\":\"7\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Metal-Based Drugs\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1155/MBD.2002.235\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Metal-Based Drugs","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1155/MBD.2002.235","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Solution Equilibria between Aluminum(III) Ion and L-histidine or L-tyrosine.
Toxic effects due to high aluminum body loads were observed in a number of conditions following ingestion of Al-containing antacids. Bio-availability of aluminum depends not only on the solubility of the ingested salt but also on the physico-chemical properties of the soluble Al complexes formed in body fluids. Amino acids may, upon interaction with Al-salts, form absorbable Al-complexes. Hence, complex formation equilibria between Al(3+) and either, L- histidine or L-tyrosine were studied by glass electrode potentiometric (0.1 mol/L LiCl ionic medium, 298 K), proton NMR and uv spectrophotometric measurements. Non linear least squares treatment of the potentiometric data indicates that in the concentration ranges: 0.5
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