In parallel, it was assessed whether AMFC could also be substrate for ACLs, through its carboxylic acid function, by carrying out reactions in the presence of butylamine as an external nucleophile on one side, and without any nucleophile on the other one, to assess AMFC's ability to react on itself and form dimer. This evaluation was carried out on a representative subset of enzymes (MsACL, TsACL and GtACL). AMFC proved to be a poor substrate for the selected ACLs, producing only traces of the corresponding butylamide in the presence of butylamine. Furthermore, in the absence of an external nucleophile, the reaction failed to produce any dimer (data not shown).