Structural basis for the functional difference between type I and type II human methionine aminopeptidases

A study is conducted to determine the crystal structure of human MetAP1 and compare the structures of a type I and type II methionine aminopeptidase (MetAP) from the same organism. It is shown that presence of excess Co(super 2)(super plus), a third cobalt iron binds in the active site region, explaining why the metal ions in excess can be inhibitory.