100 Years of peroxynitrite chemistry and 11 years of peroxynitrite biochemistry

Abstract

The paper on the unusual properties of a mixture of hydrogen peroxide and nitrous acid by Baeyer and Villiger from 1901 can be regarded as the first report on peroxynitrite. In 1990, Beckman and co-workers suggested that peroxynitrite, formed from the reaction of superoxide with nitrogen monoxide, could be a transient oxidizing species in vivo, a report that revolutionized investigations in the field of oxidative stress.     

Flavin radicals: chemistry and biochemistry

The redox properties of free and protein-bound flavin are discussed extensively. The interaction of one and two-electron reduced flavin with oxygen is emphasized.     

The chemistry of DNA damage from nitric oxide and peroxynitrite

Nitric oxide is a key participant in many physiological pathways; however, its reactivity gives it the potential to cause considerable damage to cells and tissues in its vicinity. Nitric oxide can react with DNA via multiple pathways. Once produced, subsequent conversion of nitric oxide to nitrous anhydride and/or peroxynitrite can lead to the nitrosative deamination of DNA bases such as guanine and cytosine. Complex oxidation chemistry can also occur causing DNA base and sugar oxidative modifications. This review describes the different mechanisms by which nitric oxide can damage DNA. First, the physiological significance of nitric oxide is discussed. Details of nitric oxide and peroxynitrite chemistry are then given. The final two sections outline the mechanisms underlying DNA damage induced by nitric oxide and peroxynitrite.     

Selenium in chemistry and biochemistry in comparison to sulfur

What makes selenoenzymes--seen from a chemist's view--so special that they cannot be substituted by just more analogous or adapted sulfur proteins? This review compiles and compares physicochemical properties of selenium and sulfur, synthetic routes to selenocysteine (Sec) and its peptides, and comparative studies of relevant thiols and selenols and their (mixed) dichalcogens, required to understand the special role of selenium in selenoproteins on the atomic molecular level. The biochemically most relevant differences are the higher polarizability of Se- and the lower pKa of SeH. The latter has a strikingly different pH-dependence than thiols, with selenols being active at much lower pH. Finally, selected typical enzymatic mechanisms which involve selenocysteine are critically discussed, also in view of the authors' own results.     

On various possibilities in pulsed radiation biochemistry and chemistry

Several experiments are described that relate to the application of new regimes of radiation action on enzymes in vitro and some other materials. These regimes have recently come into practice due to the appearance of a new generation of devices with very short high-energy pulses of ionizing radiation. It is shown that the term flash radiation biochemistry in its perfect sense has to be used at the condition of the overlapping individual effective interaction microvolumes (e.g. spurs and blobs) realized during a time interval (radiation pulse duration) that is low compared with the corresponding physical-chemical process. In this situation a number of unexpected effects occur at very low absolute doses. These processes are analyzed in terms of their non-stationary and non-diffusive developments.     

Lee Pedersen's work in theoretical and computational chemistry and biochemistry

Nature at the lab level in biology and chemistry can be described by the application of quantum mechanics.In many cases,a reasonable approximation to quantum mechanics is classical mechanics realized through Newton’s equations of motion.Dr.Pedersen began his career using quantum mechanics to describe the properties of small molecular complexes that could serve as models for biochemical systems.To describe large molecular systems required a drop-back to classical means and this led surprisingly to a major improvement in the classical treatment of electrostatics for all molecules,not just biological molecules.Recent work has involved the application of quantum mechanics for the putative active sites of enzymes to gain greater insight into the key steps in enzyme catalysis.