Acrylamide quenching of Yt-base fluorescence in aqueous solution.
Acrylamide was found to be an effective quencher of Yt-base (Y-4,9-dihydro-4,6-dimethyl-9-oxo-1H-imidazo-1,2a-purine) in water. In the absence of collisional quenching the decay of Yt-base in water is predominantly a single exponential. The intensity decays become increasingly heterogeneous when quenched by acrylamide. The frequency-domain data were analyzed using the radiation model, which provides estimates of molecular parameters characteristic of the system. The mutual diffusion coefficient at 20 degrees C was found to be 0.5 x 10(5) cm2/s, the Yt-base acrylamide interaction radius was 8 A, and the rate constant for quenching was 100 cm/s. These values indicate that quenching is diffusion-limited, i.e., the encounter complex is deactivated at least 2-fold faster than the rate of diffusive encounters.
Gryczynski
I
I
University of Maryland School of Medicine, Department of Biological Chemistry, Baltimore 21201.
Johnson
M L
ML
Lakowicz
J R
JR
D020106:Acrylamide; D000178:Acrylamides; D006147:Guanine / Q000031:analogs & derivatives* / Q000032:analysis; D008433:Mathematics; D012996:Solutions; D013050:Spectrometry, Fluorescence / Q000379:methods
D000178:Acrylamides; D012996:Solutions; D020106:Acrylamide; C012099:wye; D006147:Guanine