The inhibitory activity of a broad group of known metalloenzyme inhibitors 
against a panel of metalloenzymes was evaluated. Clinically approved inhibitors 
were selected as well as several other reported metalloprotein inhibitors in 
order to represent a broad range of metal binding groups (MBGs), including 
hydroxamic acid, carboxylate, hydroxypyridinonate, thiol, and N-hydroxyurea 
functional groups. A panel of metalloenzymes, including carbonic anhydrase 
(hCAII), several matrix metalloproteinases (MMPs), angiotensin converting enzyme 
(ACE), histone deacetylase (HDAC-2), and tyrosinase (TY), was selected based on 
their clinical importance for a range of pathologies. In addition, each 
inhibitor was evaluated for its ability to remove Fe(3+) from holo-transferrin 
to gauge the ability of the inhibitors to access Fe(3+) from a primary transport 
protein. The results show that the metalloenzyme inhibitors are quite selective 
for their intended targets, suggesting that despite their ability to bind metal 
ions, metalloprotein inhibitors are not prone to widespread off-target enzyme 
inhibition activity.