Histamine, copper chelates with

The catalase-like action of hemocyanin is probably because of copper bound to one or more amino acids in the protein. Contrary to previous claims (12), arginine chelates with copper are not the only catalytically active species. For example, copper chelates with histidine and histamine are also active. The rates appear to be a first power function of copper and H202. Studies now being carried out with V. S. Sharma in our laboratories indicate that the active species is the Cu (II) L form where L represents the ligand. The copper chelate forms a ternary complex with... 

Mn2+, D.F.P.-ase is further activated by cysteine, histidine, thiolhistidine, and serine, histamine and 2 2 -dipyridyl. Reagents reacting with metal ions, SH groups and carbonyl groups inhibit D.F.P.-ase activity. Work is proceeding on the further elucidation of such mechanisms.1 In a somewhat similar connexion attention is called to the fact that the non-enzymic hydrolysis of D.F.P. is accelerated by heavy metals and their complexes, in particular by copper chelates of ethylene diamine, o-phenanthroline, 2 2 -dipyridyl and histidine.2... 

In analogy to the carboxylate binding by zinc-containing cyclodextrin 10 (see Sect. 2), Lewis acidic centers such as a copper(II) histamine unit may also serve for the chelation of the (deprotonated) 2-aminoacetate substructure of a-amino acids [51], Rizzarelli, Marchelli et al. used a respective j8-cyclodextrin derivative for the formation of the ternary complexes 36 and 37 with racemic... 

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