Effect of temperature on light-absorption and fluorescence of the peroxidase.
The absorption and fluorescence spectra of peroxidase solutions is independent of temperature in the range from 10 to 45 degrees C. Above 45 degrees C the absorption decreases in the visible range and increases in the ultraviolet. The intensity of fluorescence decreases with the increase of temperature. The temperature quenching of the fluorescence is accompanied by an energy transfer from tyrosine to tryptophan. The optimum enzyme activity is observed at about 40 degrees C, at 75 degrees C the activity ceases. The heat-induced activity change is partially reversible, the activity being restored to 40 per cent on cooling down. Enzyme activity and the activation energy of fluorescence quenching of tyrosine and tryptophan residues are given in the temperature range from 10 to 45 degrees C. The kinetical characteristics of the processes are described.
D002151:Calorimetry; D004735:Energy Transfer; D007700:Kinetics; D010544:Peroxidases / Q000378:metabolism; D010944:Plants / Q000201:enzymology; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D013816:Thermodynamics; D014364:Tryptophan / Q000032:analysis; D014443:Tyrosine / Q000032:analysis
D014443:Tyrosine; D014364:Tryptophan; D010544:Peroxidases