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Systematic characterization of the covalent interactions between (-)-epigallocatechin gallate and peptides under physiological conditions by mass spectrometry.
Rapid Commun Mass Spectrom. 2009 Apr; 23(8):1147-57.RC

Abstract

(-)-Epigallocatechin gallate (EGCG) is a major bioactive component in leaves of green tea, and has been widely investigated for its anti-tumor activity. The interaction between EGCG and the key peptides or proteins (e.g. glutathione, enzymes) in vivo is thought to be involved in the toxicity and anti-cancer mechanism of EGCG. However, the true anti-tumor mechanism of EGCG is not clear, and few studies have focused on the reactivity of EGCG toward peptides or proteins under physiological conditions (pH 7.4, 37 degrees C). In this work, the covalent interactions between EGCG and model peptides containing one or more nucleophilic residues (i.e. Arg, Cys, Met, and alpha-NH(2) of the N-terminus of peptides) under physiological condition were fully characterized using mass spectrometry. It was found that EGCG can react with the thiol groups of peptides to form adducts under physiological conditions (pH 7.4, 37 degrees C), even in the absence of the peroxidase/hydrogen peroxide system. Besides the thiol groups of peptides, it is firstly reported that EGCG also reacts with alpha-NH(2) of the N-terminus or arginine residues of model peptides to form Schiff base adducts, and the methionine residues of model peptides can be easily oxidized by hydrogen peroxide (H(2)O(2)) generated during the process of EGCG auto-oxidation to form methionine sulfoxide products. The preference for the reaction of nucleophlic residues of peptides with EGCG was determined to have the following order: Cys > alpha-NH(2) of the N-terminus > Arg. The neutral loss ions of [M+H-170](+) and [M+H-138](+) were detected in all tandem mass spectra of the EGCG adducts of peptides, which indicates that these two neutral loss ions can be considered as the characteristic neutral loss ions of peptides modified by EGCG. Results of the present research provide insights into the toxicology and anti-tumor mechanism of EGCG in vivo.

Authors+Show Affiliations

State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, 33 Life Science Park Road, Changping District, Beijing 102206, China.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19280611

Citation

Cao, Dong, et al. "Systematic Characterization of the Covalent Interactions Between (-)-epigallocatechin Gallate and Peptides Under Physiological Conditions By Mass Spectrometry." Rapid Communications in Mass Spectrometry : RCM, vol. 23, no. 8, 2009, pp. 1147-57.
Cao D, Zhang Y, Zhang H, et al. Systematic characterization of the covalent interactions between (-)-epigallocatechin gallate and peptides under physiological conditions by mass spectrometry. Rapid Commun Mass Spectrom. 2009;23(8):1147-57.
Cao, D., Zhang, Y., Zhang, H., Zhong, L., & Qian, X. (2009). Systematic characterization of the covalent interactions between (-)-epigallocatechin gallate and peptides under physiological conditions by mass spectrometry. Rapid Communications in Mass Spectrometry : RCM, 23(8), 1147-57. https://doi.org/10.1002/rcm.3985
Cao D, et al. Systematic Characterization of the Covalent Interactions Between (-)-epigallocatechin Gallate and Peptides Under Physiological Conditions By Mass Spectrometry. Rapid Commun Mass Spectrom. 2009;23(8):1147-57. PubMed PMID: 19280611.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Systematic characterization of the covalent interactions between (-)-epigallocatechin gallate and peptides under physiological conditions by mass spectrometry. AU - Cao,Dong, AU - Zhang,Yangjun, AU - Zhang,Huihui, AU - Zhong,Liangwei, AU - Qian,Xiaohong, PY - 2009/3/13/entrez PY - 2009/3/13/pubmed PY - 2009/5/27/medline SP - 1147 EP - 57 JF - Rapid communications in mass spectrometry : RCM JO - Rapid Commun Mass Spectrom VL - 23 IS - 8 N2 - (-)-Epigallocatechin gallate (EGCG) is a major bioactive component in leaves of green tea, and has been widely investigated for its anti-tumor activity. The interaction between EGCG and the key peptides or proteins (e.g. glutathione, enzymes) in vivo is thought to be involved in the toxicity and anti-cancer mechanism of EGCG. However, the true anti-tumor mechanism of EGCG is not clear, and few studies have focused on the reactivity of EGCG toward peptides or proteins under physiological conditions (pH 7.4, 37 degrees C). In this work, the covalent interactions between EGCG and model peptides containing one or more nucleophilic residues (i.e. Arg, Cys, Met, and alpha-NH(2) of the N-terminus of peptides) under physiological condition were fully characterized using mass spectrometry. It was found that EGCG can react with the thiol groups of peptides to form adducts under physiological conditions (pH 7.4, 37 degrees C), even in the absence of the peroxidase/hydrogen peroxide system. Besides the thiol groups of peptides, it is firstly reported that EGCG also reacts with alpha-NH(2) of the N-terminus or arginine residues of model peptides to form Schiff base adducts, and the methionine residues of model peptides can be easily oxidized by hydrogen peroxide (H(2)O(2)) generated during the process of EGCG auto-oxidation to form methionine sulfoxide products. The preference for the reaction of nucleophlic residues of peptides with EGCG was determined to have the following order: Cys > alpha-NH(2) of the N-terminus > Arg. The neutral loss ions of [M+H-170](+) and [M+H-138](+) were detected in all tandem mass spectra of the EGCG adducts of peptides, which indicates that these two neutral loss ions can be considered as the characteristic neutral loss ions of peptides modified by EGCG. Results of the present research provide insights into the toxicology and anti-tumor mechanism of EGCG in vivo. SN - 0951-4198 UR - https://www.unboundmedicine.com/medline/citation/19280611/Systematic_characterization_of_the_covalent_interactions_between_____epigallocatechin_gallate_and_peptides_under_physiological_conditions_by_mass_spectrometry_ L2 - https://doi.org/10.1002/rcm.3985 DB - PRIME DP - Unbound Medicine ER -