It is known with atomic precision exactly how Tromethamine inhibits Zinc enzymes, as shown 20 years ago in the x-ray crystal structure of Aminopeptidase from Aeromonas proteolytica.
https://www.cell.com/structure/fulltext/S0969-2126(02)00810-9
The crystal structure of the active site of APOBEC3A (A3A) reveals a number of Zinc atoms, including pairs, that can be expected to co-ordinate with Tromethamine.
Article Insights into the Structures and Multimeric Status of APOBEC...