Fluorescence-quenching mechanism of tryptophan. Remarkably efficient internal proton-induced quenching and charge-transfer quenching

Journal Article · Wed Mar 16 04:00:00 EST 1988 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00214a044· OSTI ID:7255990

Shizuka, H; Serizawa, M; Shimo, T; Saito, I; Matsuura, T

The fluorescence quenching of tyrptophan (Trp) in the absence and presence of 18-crown-6 in CH/sub 3/OH-H/sub 2/ (9:1), vv) mixtures has been studied by means of nanosecond time-resolved single-photon counting, fluorimetry, and photochemical H-D isotope exchange. The fluorescence intensity increases markedly with increasing concentration of 18-crown-6. The quenching can be estimated from the equation k/sub q/ = tau/sub 1//sup 1 -/ - (tau /sub 2//sup max/)/sup -1/, where tau/sub 1/ and tau/sub 1//sup max/ denote the fluorescence lifetimes for free Trp and the 1:1 Trp-18-crown-6 complex, respectively. The internal quenching originates from the electrophilic protonation of the /sup +/NH/sub 3/ group of Trp at the C-4 position of the excited indole ring plus the charge-transfer interaction between the excited indole ring and the ammonium group. The stabilization constant K/sub g/ for the 1:1 complex of Trp with 18-crown-6 has been determined by means of fluorimetry.

• Research Organization: Gunma Univ., (Japan)
• OSTI ID: 7255990
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 110:6; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
AMINO ACIDS
AROMATICS
AZAARENES
AZOLES
CARBOXYLIC ACIDS
CHEMICAL REACTION KINETICS
CHEMISTRY
DATA
DE-EXCITATION
DEUTERIUM
ELEMENTS
ENERGY TRANSFER
ENERGY-LEVEL TRANSITIONS
EXPERIMENTAL DATA
FLUORESCENCE
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROGEN
HYDROGEN ISOTOPES
INDOLES
INFORMATION
ISOTOPES
ISOTOPIC EXCHANGE
KINETICS
LIGHT NUCLEI
LUMINESCENCE
NONMETALS
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMISTRY
PYRROLES
RADIATIONLESS DECAY
REACTION KINETICS
STABLE ISOTOPES
TRYPTOPHAN