ABSTRACT
Both experimental and theoretical methodologies were employed in order to study the possibility of excited state oxyluciferin being formed as the result of the decomposition of a neutral dioxetanone. Excitation measurements in water (at different pH values) and in methanol, along with computational calculations, demonstrated that the hydroxyl-benzothiazole group of firefly dioxetanone and six oxyluciferin analogues is only deprotonated in conditions not in line with the firefly bioluminescence reaction. Thus, a new mechanism involving a neutral firefly dioxetanone must be presented in order to explain the chemiexcitation of oxyluciferin. It was also studied for the first time the interaction between a molecule involved in the bioluminescence reaction (neutral firefly dioxetanone) and the real second conformation of firefly luciferase.
Subject(s)
Heterocyclic Compounds, 1-Ring/chemistry , Indoles/chemistry , Luciferases, Firefly/chemistry , Luminescent Agents/chemistry , Pyrazines/chemistry , Firefly Luciferin/chemistry , Hydrogen-Ion Concentration , Luminescent Measurements , Molecular Structure , ThermodynamicsABSTRACT
Ultraviolet (UV) filters are vital constituents of sunscreens and other personal care products since they absorb, reflect and/or scatter UV radiation, therefore protecting us from the sun's deleterious UV radiation and its effects. However, they suffer degradation, mainly through exposure towards sunlight and from reactions with disinfectant products such as chlorine. On the basis of their increasing production and use, UV filters and their degradation products have already been detected in the aquatic environment, especially in bathing waters. This paper presents a comprehensive review on the work done so far as to identify and determine the by-products of UV filter photodegradation in aqueous solutions and those subsequent to disinfection-induced degradation in chlorinated aqueous solutions, namely swimming pools.
