Determination of the rate constant for the reaction of hydroxyl and oxide radicals with cysteine in aqueous solution

Journal Article · Mon Jan 01 04:00:00 EST 1996 · Radiation Research

DOI:https://doi.org/10.2307/3579203· OSTI ID:478306

Mezyk, S P ^[1]

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1. Univ. of Notre Dame, IN (United States)

The techniques of pulse radiolysis and absorption spectroscopy have been used to determine absolute rate constants for the reaction of hydroxyl and oxide radicals with cysteine (CysS) species in aqueous solution. Using measured equilibrium constants for radical disulfide anion formation, over the pH range 6.0-13.0, observed reaction rate constants were resolved into their constituent reactions {sup {lg_bullet}}OH + CysSH {r_arrow} H{sub 2}O + CysS{sup {lg_bullet}} and {sup {lg_bullet}}O{sup {minus}} + CysS{sup -} (+ H{sub 2}O) {r_arrow} CysS{sup {lg_bullet}} + 2OH{sup -} with calculated limiting rate constants of (5.35 {+-} 0.82) X 10{sup 9} and (3.28 {+-} 0.49) X 10{sup 8} dm{sup 3} mol{sup -1} s{sup -1}, respectively. The rate constant for hydroxyl radical reaction with CysS{sup -} was found to be the same as that for CysSH. 21 refs., 6 figs., 1 tab.

• Sponsoring Organization: USDOE
• OSTI ID: 478306
• Journal Information: Radiation Research, Journal Name: Radiation Research Journal Issue: 1 Vol. 145; ISSN 0033-7587; ISSN RAREAE
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
ABSORPTION SPECTROSCOPY
BIOCHEMICAL REACTION KINETICS
CYSTEINE
CYSTINE
DISULFIDES
EVALUATION
HYDROXYL RADICALS
OXIDES
RADIATION PROTECTION
RADIOLYSIS
STRUCTURE-ACTIVITY RELATIONSHIPS
SULFIDES