Interaction between Cu and Thiols of Biological and Environmental Importance: Case Study Using Combined Spectrophotometric/Bathocuproine Sulfonate Disodium Salt Hydrate (BCS) Assay

Crmarić, Dora; Bura-Nakić, Elvira (2023) Interaction between Cu and Thiols of Biological and Environmental Importance: Case Study Using Combined Spectrophotometric/Bathocuproine Sulfonate Disodium Salt Hydrate (BCS) Assay. Molecules, 28 (13). ISSN 1420-3049

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Abstract

Considering the biological and ecological importance of Cu–thiol interactions and the discrepancies in previous research, this study focuses on Cu interactions with biologically and ecologically relevant thiols: glutathione (GSH), L-cysteine (L-cys), 3-mercaptopropionic acid (MPA), and thioacetic acid (TAA) in aqueous solution. The addition of Cu(II) to a thiol-containing solution led to a rapid reduction of Cu(II) and the formation of a Cu(I)–thiol complex. The mechanism of Cu(II) reduction and Cu(I) complex formation as well as the kinetics of Cu(I) oxidation strongly depend on the structural properties of the individual thiols investigated. The reducing power of the investigated thiols can be summarized as follows: L-cys ≅ GSH > MPA > TAA. The reaction order, with respect to Cu(I) oxidation, also changes over the time of the reaction course. The deviation of the reaction kinetics from the first order with respect to Cu(I) in the later stages of the reaction course can be attributed to a Fenton-like reaction occurring under low thiol concentration conditions. At high Cu:thiol ratios, in the case of GSH, L-cys, and MPA, the early stage of the reaction course is characterized by high Cu(I) stability, most likely as a result of Cu(I) complexation by the thiols present in excess in the reaction mixture.

Item Type:	Article
Uncontrolled Keywords:	copper; thiols; reduction; oxidation; kinetics
Subjects:	NATURAL SCIENCES > Chemistry NATURAL SCIENCES > Biology > Biochemistry and Molecular Biology
Divisions:	Division for Marine and Enviromental Research
Projects:	Project title Project leader Project code Project type Razumijevanje pojavnosti kemijskih vrsta bakra i redoks transformacija u morskoj vodi-SeCuTrans Elvira Bura-Nakić IPCH-2020-10-4965 HRZZ
Depositing User:	Josipa Karadžole
Date Deposited:	25 Mar 2026 11:29
URI:	http://fulir.irb.hr/id/eprint/11470
DOI:	10.3390/molecules28135065

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