Question

Why it is more difficult to inhibit aspartyl proteases than serine proteases?

Answer 1

Serine proteases form a covalently bound tetrahedral intermediate during the cleavage of peptide bond. The activity of serine proteases therefore is easily suppressed by certain inhibitors that resemble the tetrahedral intermediate, and thus fill up the active site, preventing the enzyme from working properly. In case of Aspartyl proteases, these enzymes are a highly specific family of proteases and their proteolysis also occurs in a single step. This makes it difficult to inhibit the activity of aspartyl proteases, and these enzymes are only suppressed by highly specific inhibitors (Pepstatin), which is a hexa-peptide containing an unusual amino acid statine and a unique amino acid sequence.

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