Phase transitions in self-assembled alkanethiolate monolayers adsorbed onto metal clusters are generally observed at temperatures below 340 K 112,113 and the process is comparable to melting the adsorbed ligand layer to a state with increased disorder. Short (containing 8 carbon atoms) alkanethiolate layers were observed by NMR spectroscopy to be already in the liquid-like state at 298 K 114 , which means that the transition must occur at lower temperatures. Furthermore, the transition temperature was found to increase with the introduction of polar groups capable of hydrogen bonding 115 . Such hydrogen bonding could reasonably be imagined for the cysteine layer. Although, to the best of our knowledge, such a phase transition has not been reported yet for cysteine, abrupt (but reversible) acceleration of the exchange shown in our results can be satisfactorily explained by a phase transition that introduces disorder to the monolayer.