Figure 5: Mechanism of enzyme labelling by the 'mechanism-based' inactivator 1 and conformational implications. | Nature Communications

Figure 5: Mechanism of enzyme labelling by the 'mechanism-based' inactivator 1 and conformational implications.

From: A mechanism-based inactivator of glycoside hydrolases involving formation of a transient non-classical carbocation

Figure 5

(a), Postulated mechanism for inhibition of the T. maritima α-galactosidase by the mechanism-based inactivator 1. The dashed arrows to Asp-387 illustrate the possible role of this residue at the TS for carbocation formation. Asp327 is depicted in both protonation states, as the ionization state of this residue has only a small effect on the kinetics of inactivation. Bicyclic cation 10 could react, reversibly, to give cyclopropylmethyl (arrow a), cyclobutyl (arrow b) or homoallylic (arrow c) labelled Asp327 or it can react with water to give hydrolysed inactivator (ROH). (b) The two ring conformations for the bicyclo[4.1.0]heptyl inactivator 1 in which the C1–C2 bond bisects the cyclopropyl ring (left: 3H2 half-chair; right: 1,4B boat).

Back to article page