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 00:00:00 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), Vol. 29:49, Issue 49; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

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