title: Measurement of rate constants for quenching singlet oxygen with a Cypridina luciferin analog (2-methyl-6-[p-methoxyphenyl]-3,7-dihydroimidazo [1,2-a]pyrazin-3-one) and sodium azide.
abstract: The rate constants for [1O2] [MCLA] and [1O2] [NaN3] were measured by quenching the near-infrared emission (1 delta g----3 sigma g) in steady state with MCLA and NaN3, respectively. 1O2 was constantly generated by energy transfer to O2 from Ar laser-excited Rose Bengal. The Stern-Volmer plots yielded the second-order rate constants of 2.94 x 10(9) M-1 S-1 and 3.83 x 10(8) M-1 S-1 for quenching 1O2 with MCLA and NaN3 in water at pH 5.4, respectively. The 1O2 + MCLA reaction emitted light with maximum at 465 nm at pD 4.5 identical to the O(2-) + MCLA reaction.
authors.affiliation: Inaba Biophoton Project, Research Development Corporation of Japan, Miyagui.
authors.forename: S
authors.initials: S
authors.lastname: Mashiko
authors.forename: N
authors.initials: N
authors.lastname: Suzuki
authors.forename: S
authors.initials: S
authors.lastname: Koga
authors.forename: M
authors.initials: M
authors.lastname: Nakano
authors.forename: T
authors.initials: T
authors.lastname: Goto
authors.forename: T
authors.initials: T
authors.lastname: Ashino
authors.forename: I
authors.initials: I
authors.lastname: Mizumoto
authors.forename: H
authors.initials: H
authors.lastname: Inaba
mesh_terms: D001386:Azides; D007093:Imidazoles; D008163:Luminescent Measurements; D010100:Oxygen / Q000032:analysis*; D011719:Pyrazines; D026082:Singlet Oxygen; D019810:Sodium Azide; D013055:Spectrophotometry, Infrared; D013482:Superoxide Dismutase
chemical_list: D001386:Azides; D007093:Imidazoles; D011719:Pyrazines; C063412:2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo(1,2-alpha)pyrazin-3-one; D026082:Singlet Oxygen; D019810:Sodium Azide; D013482:Superoxide Dismutase; D010100:Oxygen