Organic Compounds and Amino Acids

Since amino acids form the building blocks of proteins, it is important to compare the surface adsorption behavior and electrochemical oxidation reactions of amino acids at solid electrodes in order to fully understand the behavior of proteins under similar experimental conditions and the role of different functional groups in the adsorption behavior of these compounds. 

Studies were also made by Horanyi with methionine, and the potential dependence of the adsorption in alkaline solution was found to be very similar to that observed for other amino acids. The presence of the -S-CH3 group did not significantly modify the characteristic adsorption 

Horanyi et al extended these studies to the electrosorption of a C-labeled tetrapeptide (Arg-Lys-Asp-Val) at smooth gold and platinized electrodes in acid and alkaline media. A significant difference was found between the adsorption behavior of the peptide in acid and in alkaline media in the case of the gold electrode. In an alkaline medium a strong chemisorption was observed, whereas in acid medium loosely adsorbed species were formed, similar to the behavior observed with the amino acids. In all cases, strong chemisorption was observed over a wide potential range (200-1000 mV vs. RHE). 

A series of studies was made by Roscoe and co-workers on the adsorption and electrochemical oxidation mechanisms of the amino acids glycine, a- and ) -alanine, and a-, and y-aminobutyric acid at a platinum electrode in order to determine the role that the position of the amino group plays in the surface adsorption properties and subsequent oxidation of these amino acids. The investigations were made in aqueous solutions at pH 1,7, and 13 using steady-state current-potential measure- 

The adsorbed intermediate species was then hydrolyzed anodically to form the next lower aldehyde  

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