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Reactivity of sulfenic acid in human serum albumin.
Biochemistry. 2008 Jan 08; 47(1):358-67.B

Abstract

Sulfenic acid is formed upon oxidation of thiols and is a central intermediate in the redox modulation of an increasing number of proteins. Methods for quantifying or even detecting sulfenic acid are scarce. Herein, the reagent 7-chloro-4-nitrobenz-2-oxa-1,3-diazole was determined not to be suitable as a chromophoric probe for sulfenic acid in human serum albumin (HSA-SOH) because of lack of specificity. Thionitrobenzoate (TNB) reacted with HSA exposed to hydrogen peroxide, but not control or thiol-blocked HSA. The reaction was biphasic. The first phase was approximately 20-fold faster than the second phase and first order in HSA-SOH and TNB (105 +/- 11 M-1 s-1, 25 degrees C, pH 7.4), allowing quantitative data on HSA-SOH formation and reactivity to be obtained. Exposure of reduced HSA (0.5 mM) to hydrogen peroxide (4 mM, 37 degrees C, 4 min) yielded 0.18 +/- 0.02 mol of HSA-SOH per mol of HSA. HSA-SH reacted with hydrogen peroxide at 2.7 +/- 0.7 M-1 s-1 (37 degrees C, pH 7.4), while HSA-SOH reacted at 0.4 +/- 0.2 M-1 s-1, yielding sulfinic acid (HSA-SO2H), as detected by mass spectrometry. The rate constants of HSA-SOH with targets of analytical interest such as dimedone and sodium arsenite were determined. HSA-SOH did not react appreciably with the plasma reductants ascorbate or urate, nor with free basic amino acids. In contrast, HSA-SOH reacted rapidly with the plasma thiols cysteine, glutathione, homocysteine, and cysteinylglycine at 21.6 +/- 0.2, 2.9 +/- 0.5, 9.3 +/- 0.9, and 55 +/- 3 M-1 s-1 (25 degrees C, pH 7.4), respectively, supporting a role for HSA-SOH in the formation of mixed disulfides.

Authors+Show Affiliations

Laboratorios Enzimología, Facultad de Ciencias, Universidad de la República, Uruguay.No affiliation info availableNo affiliation info availableNo 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, N.I.H., Extramural
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18078330

Citation

Turell, Lucía, et al. "Reactivity of Sulfenic Acid in Human Serum Albumin." Biochemistry, vol. 47, no. 1, 2008, pp. 358-67.
Turell L, Botti H, Carballal S, et al. Reactivity of sulfenic acid in human serum albumin. Biochemistry. 2008;47(1):358-67.
Turell, L., Botti, H., Carballal, S., Ferrer-Sueta, G., Souza, J. M., Durán, R., Freeman, B. A., Radi, R., & Alvarez, B. (2008). Reactivity of sulfenic acid in human serum albumin. Biochemistry, 47(1), 358-67.
Turell L, et al. Reactivity of Sulfenic Acid in Human Serum Albumin. Biochemistry. 2008 Jan 8;47(1):358-67. PubMed PMID: 18078330.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Reactivity of sulfenic acid in human serum albumin. AU - Turell,Lucía, AU - Botti,Horacio, AU - Carballal,Sebastián, AU - Ferrer-Sueta,Gerardo, AU - Souza,José M, AU - Durán,Rosario, AU - Freeman,Bruce A, AU - Radi,Rafael, AU - Alvarez,Beatriz, Y1 - 2007/12/14/ PY - 2007/12/15/pubmed PY - 2008/3/1/medline PY - 2007/12/15/entrez SP - 358 EP - 67 JF - Biochemistry JO - Biochemistry VL - 47 IS - 1 N2 - Sulfenic acid is formed upon oxidation of thiols and is a central intermediate in the redox modulation of an increasing number of proteins. Methods for quantifying or even detecting sulfenic acid are scarce. Herein, the reagent 7-chloro-4-nitrobenz-2-oxa-1,3-diazole was determined not to be suitable as a chromophoric probe for sulfenic acid in human serum albumin (HSA-SOH) because of lack of specificity. Thionitrobenzoate (TNB) reacted with HSA exposed to hydrogen peroxide, but not control or thiol-blocked HSA. The reaction was biphasic. The first phase was approximately 20-fold faster than the second phase and first order in HSA-SOH and TNB (105 +/- 11 M-1 s-1, 25 degrees C, pH 7.4), allowing quantitative data on HSA-SOH formation and reactivity to be obtained. Exposure of reduced HSA (0.5 mM) to hydrogen peroxide (4 mM, 37 degrees C, 4 min) yielded 0.18 +/- 0.02 mol of HSA-SOH per mol of HSA. HSA-SH reacted with hydrogen peroxide at 2.7 +/- 0.7 M-1 s-1 (37 degrees C, pH 7.4), while HSA-SOH reacted at 0.4 +/- 0.2 M-1 s-1, yielding sulfinic acid (HSA-SO2H), as detected by mass spectrometry. The rate constants of HSA-SOH with targets of analytical interest such as dimedone and sodium arsenite were determined. HSA-SOH did not react appreciably with the plasma reductants ascorbate or urate, nor with free basic amino acids. In contrast, HSA-SOH reacted rapidly with the plasma thiols cysteine, glutathione, homocysteine, and cysteinylglycine at 21.6 +/- 0.2, 2.9 +/- 0.5, 9.3 +/- 0.9, and 55 +/- 3 M-1 s-1 (25 degrees C, pH 7.4), respectively, supporting a role for HSA-SOH in the formation of mixed disulfides. SN - 0006-2960 UR - https://www.unboundmedicine.com/medline/citation/18078330/Reactivity_of_sulfenic_acid_in_human_serum_albumin_ L2 - https://dx.doi.org/10.1021/bi701520y DB - PRIME DP - Unbound Medicine ER -