Subject tracer molecule

Nonsteady behavior of electrochemical systems was observed by -> Fechner as early as 1828 [ii]. Periodic or chaotic changes of electrode potential under - gal-vanostatic or open-circuit conditions and similar variation of -> current under potentiostatic conditions have been the subject of numerous studies [iii, iv]. The electrochemical systems, for which interesting dynamic behavior has been reported include anodic or open-circuit dissolution of metals [v-vii], electrooxidation of small organic molecules [viii-xiv] or hydrogen, reduction of anions [xv, xvi] etc. [ii]. Much effort regarding the theoretical description and mathematical modeling of these complex phenomena has been made [xvii-xix]. Especially studies that used combined techniques, such as radiotracer (- tracer methods)(Fig. 1) [x], electrochemi-... 

Reactions involving cyclic molecules have been the subject of a number of studies employing tracer techniques. 

The myth that phospholipids were slowly turning-over structural molecules was exploded by the Danish chemist Hevesy who in 1935 demonstrated that the radioactive isotope of phosphorus ( P) could be rapidly incorporated as inorganic orthophosphate into tissue phospholipids. By this time it was also known that the stable isotopes ( H) and ( N) were incorporated into proteins and fats. These studies gave rise to two important concepts. First, molecules (including lipids) in living cells were subject to turnover and were continuously replaced (or parts of them were replaced) by a combination of synthesis and breakdown. Secondly, tracer methods showed the presence of metabolic pools. These are circulating mixtures of chemical substances, in partial or total equilibrium with similar substances derived by release from... 

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