+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ PDF Full Text
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Translate
+ Recently Requested

Oxygen-18 tracer studies of enzyme reactions with radical/cation diagnostic probes

Oxygen-18 tracer studies of enzyme reactions with radical/cation diagnostic probes

Biochemical and Biophysical Research Communications 338(1): 240-249

This review considers reactions of enzymes with the cyclopropanoid radical/cation diagnostic probes norcarane, 1,1-dimethylcyclopropane, and 1,1-diethylcyclopropane as elaborated by the use of 18O2 and 18OH2 to trace the origin of O-atoms incorporated during catalysis. The reactions of soluble and integral membrane diiron enzymes are summarized and compared to results obtained from cytochrome P450 studies. Norcarane proved to be an excellent substrate for the diiron enzyme toluene 4-monooxygenase and its engineered isoforms, with kcat and coupling between NADH utilization and total hydroxylated products comparable to that determined for toluene, the natural substrate. Results obtained with toluene 4-monooxygenase show that the un-rearranged and radical-rearranged alcohol products have a high percentage of O-atom incorporation (>80-95%) from O2, while the cation-derived ring-expansion products have O-atom incorporation primarily derived from solvent water. Mechanistic possibilities accounting for this difference are discussed.

(PDF emailed within 0-6 h: $19.90)

Accession: 049839067

Download citation: RISBibTeXText

PMID: 16168953

DOI: 10.1016/j.bbrc.2005.08.217

Related references

Remarkable aliphatic hydroxylation by the diiron enzyme toluene 4-monooxygenase in reactions with radical or cation diagnostic probes norcarane, 1,1-dimethylcyclopropane, and 1,1-diethylcyclopropane. Biochemistry 43(50): 15688-15701, 2004

Gas-phase reactions of the atomic oxygen radical cation with halogenated compounds. Physical Chemistry Chemical Physics 15(2): 561-567, 2012

Reactions of a N-acyliminium ion pool with benzylsilanes. Implication of a radical/cation/radical cation chain mechanism involving oxidative C-Si bond cleavage. Journal of the American Chemical Society 129(7): 1902-1903, 2007

Radical Cation/Radical Reactions: A Fourier Transform Ion Cyclotron Resonance Study of Allyl Radical Reacting with Aromatic Radical Cations. International Journal of Mass Spectrometry 287(1-3): 8-15, 2010

Selective radical probes in enzyme studies. International Journal of Radiation Biology & Related Studies in Physics Chemistry & Medicine 20(2): 181, 1971

Predictive studies of H-atom abstraction reactions by an iron(IV)-oxo corrole cation radical oxidant. Chemical Communications 48(29): 3491-3493, 2012

Radical cage reactions of metalloporphyrins and the use of radical probes of porphyrin conformation in model membranes. Abstracts of Papers American Chemical Society 204(1-2): ORGN 291, 1992

The oxidation of trimethylamine by hydroxyl radicals in aqueous solution as studied by pulse radiolysis esr and product analysis the reactions of the alkylamine radical cation the aminoalkyl radical and the protonated aminoalkyl radical. Zeitschrift fuer Naturforschung Teil B Anorganische Chemie Organische Chemie 41(4): 505-513, 1986

The formation of aminopyrine cation radical by the peroxidase activity of prostaglandin H synthase and subsequent reactions of the radical. Journal of Biological Chemistry 260(3): 1601-1607, 1985

Tandem polar/radical crossover sequences for the formation of fused and bridged bicyclic nitrogen heterocycles involving radical ionic chain reactions, and alkene radical cation intermediates, performed under reducing conditions: scope and limitations. Journal of the American Chemical Society 125(26): 7942-7947, 2003

The stable radical cation of thiophene annelated with bicyclo[2.2.2]octene and its reaction with triplet oxygen to give a protonated cation of 2-butene-1,4-dione derivative. Chemical Communications: 1192-1193, 2002

Use of electrospray ionization mass spectrometry for the investigation of radical cation chain reactions in solution: detection of transient radical cations. Analytical and Bioanalytical Chemistry 377(7-8): 1108-1114, 2003

Investigation of reactive intermediates of chemical reactions in solution by electrospray ionization mass spectrometry: radical cation chain reactions. Angewandte Chemie 42(38): 4700-4703, 2003

Cation radical probes Development and application to metalloporphyrin-catalyzed epoxidation. Journal of the American Chemical Society 114(27): 10968-10969, 1992

Novel fluorescence probes for hydroxyl radical, singlet oxygen and nitric oxide MO calculation-assisted development of new functional fluorescence probes. Free Radical Biology & Medicine 29(Supplement 1): S120, 2000