(A) Strategy for analyzing channeling in PutA. In a channeling mechanism, the P5C intermediate (I) is transferred directly between the PRODH and P5CDH active sites of PutA. For a non-channeling control reaction, monofunctional variants are used that can only catalyze the coupled reaction via a diffusion mechanism. Procura Puta? Tratamos de si.. Veja o perfil de Puta em LiveJasmin!. 18 Feb Structures of the bifunctional enzyme proline utilization A (PutA) reveal an elaborate and dynamic tunnel system featuring a Å-long substrate-channeling path that links the two active sites. Furthermore, we have identified the elusive quinone-binding site of PutA, which provides insight into how PutAs.