Hydroxyl radical induced decarboxylation and deamination of 2-methylalanine catalyzed by copper ions

Journal Article · Wed Jun 10 00:00:00 EDT 1992 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00038a026· OSTI ID:6975324

Goldstein, S; Czapski, G ^[1]; Cohen, H; Meyerstein, D ^[2]

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1. The Hebrew Univ. of Jerusalem (Israel)
2. Ben-Gurion Univ. of the Negev, Beer-Sheva (Israel)

Using the pulse radiolysis technique, the rate constants of the reactions of [sup [center dot]]CH[sub 2]C(CH[sub 3])(NH[sub 3][sup +])COO[sup [minus]] (the radical derived via H-abstraction from 2-methylalanine) with Cu[sup 2+][sub aq] and Cu[sup +][sub aq] to form unstable intermediates with a copper-carbon [sigma]-bond have been determined to be (1.3 [plus minus] 0.3) [times] 10[sup 7] and (1.3 [plus minus] 0.2) [times] 10[sup 9] M[sup [minus]1]s[sup [minus]1], respectively. In the case of cupric ions, the transient decomposes via a [beta]-carboxyl elimination reaction yielding Cu[sup +][sub aq], CH[sub 3]COCH[sub 3], and CO[sub 2], whereas in the case of cuprous ions it decomposes via a [beta]-amine elimination reaction yielding Cu[sup 2+][sub aq], CH[sub 2][double bond]C(CH[sub 3])COO[sup [minus]], and NH[sub 3]. A reaction mechanism for aliphatic radical induced amino acid damage catalyzed by copper ions in different oxidation states is suggested. This mechanism describes a plausible new pathway for biological damage induced by free radicals.

• OSTI ID: 6975324
• Journal Information: Inorganic Chemistry; (United States), Journal Name: Inorganic Chemistry; (United States) Vol. 31:12; ISSN 0020-1669; ISSN INOCAJ
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
ABSORPTION SPECTRA
ALANINES
AMINO ACIDS
BIOLOGICAL EFFECTS
CARBOXYLIC ACIDS
CATALYTIC EFFECTS
CHARGED PARTICLES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COPPER
DEAMINATION
DECARBOXYLATION
DECOMPOSITION
ELEMENTS
HYDROXYL RADICALS
IONS
KINETICS
METALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
RADIATION EFFECTS
RADICALS
RADIOLYSIS
REACTION INTERMEDIATES
REACTION KINETICS
SPECTRA
TRANSITION ELEMENTS
VALENCE