CO sub 2 ter dot minus radical induced cleavage of disulfide bonds in proteins. A gamma-ray and pulse radiolysis mechanistic investigation

Journal Article · Sat Dec 01 04:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00501a016· OSTI ID:5530099

Favaudon, V; Tourbez, H; Lhoste, J-M ^[1]; Houee-Levin, C ^[2]

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1. Institut Curie-Biologie, Orsay (France)
2. Univ. Rene-Descartes, Paris (France)

Disulfide bond reduction by the CO{sub 2}{sup {center dot}{minus}} radical was investigated in aponeocarzinostatin, aporiboflavin-binding protein, and bovine immunoglobulin. Protein-bound cysteine free thiols were formed under {gamma}-ray irradiation in the course of a pH-dependent and protein concentration dependent chain reaction. The chain efficiency increased upon acidification of the medium, with an apparent pK{sub a} around 5, and decreased abruptly below pH 3.6. It decreased also at neutral pH as cysteine accumulated. From pulse radiolysis analysis, CO{sub 2}{sup {center dot}{minus}} proved able to induce rapid one-electron oxidation of thiols and of tyrosine phenolic groups in addition to one-electron donation to exposed disulfide bonds. The bulk rate constant of CO{sub 2}{sup {center dot}{minus}} uptake by the native proteins was 5{minus} to 10-fold faster at pH 3 than at pH 8, and the protonated form of the disulfide radical anion, appeared to be the major protein radical species formed under acidic conditions. Formation of the disulfide radical cation, phenoxyl radical Tyr-O{sup {center dot}} disproportionation, and phenoxyl radical induced oxidation of preformed thiol groups should also be taken into consideration to explain the fate of the oxygen-centered phenoxyl radical.

• OSTI ID: 5530099
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Journal Issue: 49 Vol. 29:49; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
AMINO ACIDS
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
ANTINEOPLASTIC DRUGS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
CHEMICAL BONDS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
COBALT 60
COBALT ISOTOPES
CYSTEINE
DAYS LIVING RADIOISOTOPES
DECOMPOSITION
DISULFIDES
DOSE-RESPONSE RELATIONSHIPS
DRUGS
ELECTROMAGNETIC RADIATION
EVEN-ODD NUCLEI
GAMMA RADIATION
GLOBULINS
IMMUNOGLOBULINS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZING RADIATIONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LIGHT NUCLEI
MINUTES LIVING RADIOISOTOPES
NEOCARCINOSTATIN
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PH VALUE
PHENOXY RADICALS
PROTEINS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RADICALS
RADIOINDUCTION
RADIOISOTOPES
RADIOLYSIS
RADIOMIMETIC DRUGS
REDUCTION
SULFUR 35
SULFUR ISOTOPES
THIOLS
YEARS LIVING RADIOISOT