EurekaMag.com logo
+ Site Statistics
References:
53,214,146
Abstracts:
29,074,682
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

The lumiflavin sensitized photooxidation of substituted phenylalanines and tyrosines



The lumiflavin sensitized photooxidation of substituted phenylalanines and tyrosines



Photobiochemistry & Photobiophysics 10(3): 149-162



Steady-state kinetic and flash photolysis techniques were used to study the relationships between the structures of substituted phenylalanines and tyrosines and their susceptibility to lumiflavin-sensitized photooxidation. Phenylalanine is oxidized at a moderate rate as measured by oxygen uptake; in most cases, substitution of progressively better electron donating (activating) groups such as -OCH3 (as in 4-methoxyphenylalanine), -OH (as in tyrosine) and -NH2 (as in p-aminophenylalanine) to the benzenoid ring results in increased rates of photooxidation. Substitution of additional activating groups to the ring gives even greater rates. Substitution of a deactivating group such as -NO2 (as in p-nitrophenylalanine) results in a decreased photooxidation rate; additional deactivating groups produce a further decrease. Thus, in most cases, the rate determining step in the photooxidation mechanism is largely dependent on the presence and position of an electron donating substituent on the benzenoid ring. A previous study of the eosin Y-sensitized photooxidation of substituted phenylalanines gave analogous results with the major difference being that eosin Y does not sensitize the photooxidation of phenylalanine and 4-methoxyphenylalanine. The flash photolysis studies show that triplet lumiflavin is a better oxidizing agent than triplet eosin since phenylalanine and 4-methoxyphenylalanine react efficiently with triplet flavin but not with triplet eosin; this may account for the major differences observed between the eosin Y- and lumiflavin-sensitized photooxidations.

(PDF 0-2 workdays service: $29.90)

Accession: 006712366

Download citation: RISBibTeXText



Related references

The eosin sensitized photo oxidation of substituted phenyl alanines and tyrosines. Photochemistry and Photobiology 25(5): 465-476, 1977

Flavin sensitized photooxidation of substituted phenols in natural water. Journal of Contaminant Hydrology 9(1-2): 207-219, 1992

Lumiflavin sensitized photooxygenation of indole. Photochemistry & Photobiology 48(5): 561-566, 1988

Action of substituted phenylalanines on Escherichia coli. Biochemical Journal 54(1): 1-13, 1953

Resistance of aryl-substituted phenylalanines to decarboxylation in the rat. General Pharmacology 31(3): 437-440, Sept, 1998

Quenching of excited triplet lumiflavin by lumiflavin radicals formed in its t t reaction. Photochemistry & Photobiology 53(2): 175-180, 1991

Facile asymmetric synthesis beta-substituted phenylalanines. Abstracts of Papers American Chemical Society 217(1-2): MEDI 228, 1999

Transamination of ring-substituted L-phenylalanines by an extract from rat liver mitochondria. Canadian Journal of Biochemistry 51(4): 407-411, 1973

Synthesis resolution and characterization of ring substituted phenylalanines and tryptophans. International Journal of Peptide & Protein Research 30(1): 13-21, 1987

Enantioselective synthesis of 4-substituted phenylalanines by cross-coupling reactions. Abstracts of Papers American Chemical Society 216(1-3): ORGN 365, 1998

3-Substituted phenylalanines as selective AMPA- and kainate receptor ligands. Bioorganic & Medicinal Chemistry 17(17): 6390-6401, 2009

Efficient cycloreversion of cis,syn-thymine photodimer by a Zn2+ -1,4,7,10-tetraazacyclododecane complex bearing a lumiflavin and tryptophan by chemical reduction and photoreduction of a lumiflavin unit. Journal of Biological Inorganic Chemistry 11(8): 1007-1023, 2006

A mechanism for hydroxylation by tyrosine hydroxylase based on partitioning of substituted phenylalanines. Biochemistry 35(22): 6969-6975, 1996

32] Dye-sensitized photooxidation. Methods in Enzymology 25: 401-409, 2016