Action of Atomic Hydrogen on Ferri-Cytochrome c in Aqueous Solution

Abstract

ATOMIC hydrogen is one of the simplest chemical reagents. Its structure can be described in exact theoretical terms. In aqueous solution it interacts only relatively weakly with the solvent. It is neutral and thus not influenced by ionic effects in its reaction with specific substrates. Therefore its reactions are of interest from the point of view of fundamental chemical kinetics in aqueous solutions. Recently, a method has been established for the investigation of the quantitative aspects of the reactivity of atomic hydrogen with various substrates dissolved in aqueous solutions¹. Using a high-frequency electrode-less discharge to dissociate pure hydrogen gas into hydrogen-atoms and passing these under carefully controlled conditions into aqueous solution, it was shown that the reactive species is identical in its reactions with hydrogen-atoms produced by ionizing radiations or by ultra-violet light². Therefore these reactions serve to elucidate also, independently, some aspects of the mechanism of the action of ionizing radiations or ultra-violet light on such systems. In this method, however, hydrogen atoms are the only reactive species present so that their specific action may be examined separately. The reactions of simple substrates (inorganic ions^1,2; their inorganic complexes³; simple organic solutes⁴) were used to establish details of the reactivity of hydrogen atoms. The work was extended to enzymes (chymotrypsin^5a, trypsin^5b, ribonuclease^5c) to elucidate the action on biologically interesting substrates.