Catalytic activities and coordination environments of the copper ions in the imidazole clusters of histidine-peptides, His(His)nGly and N-acetyl-His(His)nGly (n = 3, 8, and 18).

The copper ions in the imidazole-clusters of histidine-oligopeptide, His(His)nGly (n = 18) and N-acetyl-His(His)nGly(n = 8 and 18), showed the d-d transition bands at 520 nm and 630 nm and oxidase-like activities. Those with the d-d bands at 480 nm and 550 nm did not have the activity.