PEPTIDYLGLYCINE ALPHA-AMIDATING REACTION - EVIDENCE FOR A 2-STEP MECHANISM INVOLVING A STABLE INTERMEDIATE AT NEUTRAL PH

In our previous study of the rat brain α-amidating activity, we suggested that a protein of 41 kdal (41K protein) that shows no α-amidating activity is required for the reaction at neutral pH in addition to an α-amidating enzyme of 36 kdal(36K enzyme). Here we report on the purification of both proteins to near homogeneity and provide evidence that α-amidation proceeds via a two-step mechanism involving a stable intermediate at neutral pH, which is initially formed by the 36K enzyme and then readily converted into an amide product by the 41K protein. © 1990.