ON THE MECHANISM OF CATALYSIS BY A METAL-FREE HYDROGENASE FROM METHANOGENIC ARCHAEA - ENZYMATIC TRANSFORMATION OF H-2 WITHOUT A METAL AND ITS ANALOGY TO THE CHEMISTRY OF ALKANES IN SUPERACIDIC SOLUTION

Substrate activation by protonation to form a “superelectrophile” could be a new mechanism for enzyme catalysis. The hydrogenation below, catalyzed by an enzyme containing no redox‐active transition metal, is very similar to the reaction of carbocations with hydrogen under superacidic conditions. This suggests that in the enzyme‐bound state the stable formamidinium ion 1 may also be converted into a highly reactive carbocation, probably through N‐protonation and conformational locking. (Figure Presented.) Copyright © 1995 by VCH Verlagsgesellschaft mbH, Germany