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Minor thiols cysteine and cysteinylglycine regulate the competition between glutathione and protein SH groups in human platelets subjected to oxidative stress.
Arch Biochem Biophys. 2000 Aug 01; 380(1):1-10.AB

Abstract

Changes in the concentrations of protein-mixed disulfides (XS-SP) of glutathione (GSH), cysteine (CSH), and cysteinylglycine (CGSH) were studied in human platelets treated with diamide and t-BOOH in timecourse experiments (time range, 1-30 min) in order to understand the contribution of minor thiols CSH and CGSH to the regulation of glutathione-protein mixed disulfides (GS-SP). Diamide was much more potent than t-BOOH in altering the platelet thiol composition of XS-SP (threshold dose: diamide, 0.03 mM; t-BOOH, 0.5 mM) and caused reversible XS-SP peaks whose magnitude was related to the concentration of free thiols in untreated cells. Thus maximum levels of GS-SP (8 min after 0.4 mM diamide) were about 16-fold higher than those of controls (untreated platelets, GS-SP = 0.374 nmol/10(9) platelets), whereas those of CS-SP and CGS-SP were only 4-fold increased (untreated platelets, CS-SP = 0.112 nmol/10(9) platelets; CGS-SP = 0.024 nmol/10(9) platelets). The greater effects of diamide with respect to t-BOOH were explained on the basis of the activities of fast reactive protein SH groups for diamide and glutathione reductase (GR) and glucose-6-phosphate dehydrogenase (G-6-PDH) for t-BOOH. The addition of cysteine (0.3 mM, at 4 min) after treatment of platelets with 0.4 mM diamide increased the rate of reversal of GS-SP peaks to normal values, but also caused a relevant change in CGS-SP with respect to that of platelets treated with diamide alone. An increased gamma-glutamyltranspeptidase activity was found in platelets treated with diamide. Moreover, untreated platelets were found to release and hydrolyze GSH to CGSH and CSH. Ratios of thiols/disulfides (XSH/XSSX) and activities of GR and G-6PDH were also related to a high reducing potential exerted by GSH but not by minor thiols. The lower mass and charge of minor thiols is a likely requisite of the regulation of GS-SP levels in platelets.

Authors+Show Affiliations

Department of Neuroscience-Pharmacology Section, University of Siena, Via A. Moro 4, Siena, 53100, Italy.No affiliation info availableNo affiliation info availableNo 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

10900126

Citation

Giustarini, D, et al. "Minor Thiols Cysteine and Cysteinylglycine Regulate the Competition Between Glutathione and Protein SH Groups in Human Platelets Subjected to Oxidative Stress." Archives of Biochemistry and Biophysics, vol. 380, no. 1, 2000, pp. 1-10.
Giustarini D, Campoccia G, Fanetti G, et al. Minor thiols cysteine and cysteinylglycine regulate the competition between glutathione and protein SH groups in human platelets subjected to oxidative stress. Arch Biochem Biophys. 2000;380(1):1-10.
Giustarini, D., Campoccia, G., Fanetti, G., Rossi, R., Giannerini, F., Lusini, L., & Di Simplicio, P. (2000). Minor thiols cysteine and cysteinylglycine regulate the competition between glutathione and protein SH groups in human platelets subjected to oxidative stress. Archives of Biochemistry and Biophysics, 380(1), 1-10.
Giustarini D, et al. Minor Thiols Cysteine and Cysteinylglycine Regulate the Competition Between Glutathione and Protein SH Groups in Human Platelets Subjected to Oxidative Stress. Arch Biochem Biophys. 2000 Aug 1;380(1):1-10. PubMed PMID: 10900126.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Minor thiols cysteine and cysteinylglycine regulate the competition between glutathione and protein SH groups in human platelets subjected to oxidative stress. AU - Giustarini,D, AU - Campoccia,G, AU - Fanetti,G, AU - Rossi,R, AU - Giannerini,F, AU - Lusini,L, AU - Di Simplicio,P, PY - 2000/7/20/pubmed PY - 2000/9/9/medline PY - 2000/7/20/entrez SP - 1 EP - 10 JF - Archives of biochemistry and biophysics JO - Arch Biochem Biophys VL - 380 IS - 1 N2 - Changes in the concentrations of protein-mixed disulfides (XS-SP) of glutathione (GSH), cysteine (CSH), and cysteinylglycine (CGSH) were studied in human platelets treated with diamide and t-BOOH in timecourse experiments (time range, 1-30 min) in order to understand the contribution of minor thiols CSH and CGSH to the regulation of glutathione-protein mixed disulfides (GS-SP). Diamide was much more potent than t-BOOH in altering the platelet thiol composition of XS-SP (threshold dose: diamide, 0.03 mM; t-BOOH, 0.5 mM) and caused reversible XS-SP peaks whose magnitude was related to the concentration of free thiols in untreated cells. Thus maximum levels of GS-SP (8 min after 0.4 mM diamide) were about 16-fold higher than those of controls (untreated platelets, GS-SP = 0.374 nmol/10(9) platelets), whereas those of CS-SP and CGS-SP were only 4-fold increased (untreated platelets, CS-SP = 0.112 nmol/10(9) platelets; CGS-SP = 0.024 nmol/10(9) platelets). The greater effects of diamide with respect to t-BOOH were explained on the basis of the activities of fast reactive protein SH groups for diamide and glutathione reductase (GR) and glucose-6-phosphate dehydrogenase (G-6-PDH) for t-BOOH. The addition of cysteine (0.3 mM, at 4 min) after treatment of platelets with 0.4 mM diamide increased the rate of reversal of GS-SP peaks to normal values, but also caused a relevant change in CGS-SP with respect to that of platelets treated with diamide alone. An increased gamma-glutamyltranspeptidase activity was found in platelets treated with diamide. Moreover, untreated platelets were found to release and hydrolyze GSH to CGSH and CSH. Ratios of thiols/disulfides (XSH/XSSX) and activities of GR and G-6PDH were also related to a high reducing potential exerted by GSH but not by minor thiols. The lower mass and charge of minor thiols is a likely requisite of the regulation of GS-SP levels in platelets. SN - 0003-9861 UR - https://www.unboundmedicine.com/medline/citation/10900126/Minor_thiols_cysteine_and_cysteinylglycine_regulate_the_competition_between_glutathione_and_protein_SH_groups_in_human_platelets_subjected_to_oxidative_stress_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0003-9861(00)91847-2 DB - PRIME DP - Unbound Medicine ER -