α-Amylase, from pig pancreas Inhibitors

Chemical inhibitors of α-amylase offer diverse mechanisms by which they can impede the enzyme's capacity to break down starches into sugars. Acarbose is such an inhibitor, functioning by competitively binding to the enzyme's active site, which mimics the structure of its natural substrates. This results in a reversible blockage, preventing the normal catalytic process from occurring. Similarly, tendamistat forms a stable complex with α-amylase through high-affinity binding, which directly obstructs the enzyme's starch-hydrolyzing ability. Montbretin A also engages with α-amylase, but distinguishes itself by its highly specific interaction with the active site, effectively barring polysaccharide substrates from entering the site. Berberine and oleanolic acid are two compounds that non-covalently bind to α-amylase, leading to a conformational alteration of the enzyme that results in diminished enzymatic action towards starch molecules.

Continuing this pattern of interaction, ursolic acid and epigallocatechin gallate (EGCG) are known to interact with α-amylase in a way that changes the enzyme's configuration, with EGCG notably binding at multiple sites which causes an allosteric inhibition. Further, flavonoids such as myricetin, luteolin, morin, quercetin, and rutin all inhibit α-amylase activity by forming complexes with the enzyme. Myricetin and luteolin directly engage with the active site, restricting substrate access and thus the enzyme's activity. Morin and quercetin operate on a similar principle, with their binding inducing a conformational change that hampers the enzyme's ability to bind starch molecules effectively. Lastly, rutin's interaction with α-amylase causes structural alterations that impede the necessary positioning of substrate molecules for efficient catalysis, illustrating the diverse array of mechanisms by which α-amylase can be inhibited.