Phenol coupling initiated by one-electron oxidation of tyrosine units in peptides and histone.
| dc.contributor.author | Prütz, W A | |
| dc.contributor.author | Butler, John | |
| dc.contributor.author | Land, Edward J | |
| dc.date.accessioned | 2014-12-22T15:32:41Z | |
| dc.date.available | 2014-12-22T15:32:41Z | |
| dc.date.issued | 1983-08 | |
| dc.identifier.citation | Phenol coupling initiated by one-electron oxidation of tyrosine units in peptides and histone. 1983, 44 (2):183-96 Int J Radiat Biol Relat Stud Phys Chem Med | en |
| dc.identifier.issn | 0020-7616 | |
| dc.identifier.pmid | 6603438 | |
| dc.identifier.uri | http://hdl.handle.net/10541/337547 | |
| dc.description.abstract | Phenoxyl radicals generated pulse radiolytically by the reaction of N.3 with Gly-Tyr decay biomolecularly (2k = 4.7 X 10(8)M-1 s-1) with efficient formation of 2,2'-dimers, which enolize rapidly (k = 2.7 X 10(4) s-1) to produce the 2,2'-biphenolic product. The build-up of the characteristic 2,2'-biphenol fluorescence (400 nm) and absorption also indicated a delayed (k = 80 s-1) process, probably involving the phenoxyl <-> phenoxy-quinol equilibrium. About 60 per cent of the Gly-Tyr phenoxyls were found to dimerize to the 2,2'-biphenol, and a similarly efficient 2,2'-coupling seems to occur with other tyrosyls, such as Lys-Tyr-Lys and histone. gamma-Radiolysis was applied to estimate relative yields of formation of 2,2'-biphenols under various conditions. Dimerization is almost completely inhibited by cysteine or oxygen, consistent with phenoxyl 'repair' by cysteine or O-.2; disproportionation of O-.2 with SOD prevents repair. The phenol 2,2'-coupling is less efficient for .OH- and inefficient for e-aq-initiation. | |
| dc.language.iso | en | en |
| dc.rights | Archived with thanks to International journal of radiation biology and related studies in physics, chemistry, and medicine | en |
| dc.subject.mesh | Dipeptides | |
| dc.subject.mesh | Dose-Response Relationship, Radiation | |
| dc.subject.mesh | Gamma Rays | |
| dc.subject.mesh | Histones | |
| dc.subject.mesh | Oxidation-Reduction | |
| dc.subject.mesh | Phenols | |
| dc.subject.mesh | Pulse Radiolysis | |
| dc.title | Phenol coupling initiated by one-electron oxidation of tyrosine units in peptides and histone. | en |
| dc.type | Article | en |
| dc.contributor.department | Universitat Freiburg, Institut fur Biophysik und Strahlenbiologie, ALbertstrasse 23, D-7800 Freiburg, FR Germany | en |
| dc.identifier.journal | International Journal of Radiation Biology and Related Studies in Physics, Chemistry, and Medicine | en |
| html.description.abstract | Phenoxyl radicals generated pulse radiolytically by the reaction of N.3 with Gly-Tyr decay biomolecularly (2k = 4.7 X 10(8)M-1 s-1) with efficient formation of 2,2'-dimers, which enolize rapidly (k = 2.7 X 10(4) s-1) to produce the 2,2'-biphenolic product. The build-up of the characteristic 2,2'-biphenol fluorescence (400 nm) and absorption also indicated a delayed (k = 80 s-1) process, probably involving the phenoxyl <-> phenoxy-quinol equilibrium. About 60 per cent of the Gly-Tyr phenoxyls were found to dimerize to the 2,2'-biphenol, and a similarly efficient 2,2'-coupling seems to occur with other tyrosyls, such as Lys-Tyr-Lys and histone. gamma-Radiolysis was applied to estimate relative yields of formation of 2,2'-biphenols under various conditions. Dimerization is almost completely inhibited by cysteine or oxygen, consistent with phenoxyl 'repair' by cysteine or O-.2; disproportionation of O-.2 with SOD prevents repair. The phenol 2,2'-coupling is less efficient for .OH- and inefficient for e-aq-initiation. |