On the effect of temperature on the ultraviolet spectra of protein chromophores.
The thermal perturbation difference spectra - TPDS (15-30 degrees C) - of N-acetyl-tyrosine-ethyl ester and o-methyl-N-acetyl-tyrosine were studied in ethyl acetate and dimethyl ether with/without the addition of butanol which served as a proton donor in hydrogen bonding. In all cases the longwave shift of the absorption spectrum is shown to be a principal factor that determines the origin of TPDS and the hydrogen bonding has no effect on these spectra. These results contradict the view that the red shift of protein chromophore spectra at the elevation of temperature is a unique feature of water as a solvent. The water-inaccessible chromophores in proteins may be perturbed by temperature increase, producing red shift.
Demchenko
A P
AP
Laboratory of Molecular Biology, Institute of Gerontology AMS USSR, 252655 Kiev-114, U.S.S.R.