Question

Predict the effect of mutating Asp 102 and His 57 (consider both mutations are introduced separately) of trypsin to Asn and Thr respectively. What impact would these changes have on the ability of the enzyme to bind to its substrate and to catalyze its normal reaction?

Answer 1

Mutation of asp 102 to asn: Aspartate is a negatively charged amino acid while aspargine is a uncharged polar amino acid it will not allow the charge relay system to function in the catalytic triad of trypsin active site.

Mutation if His 57 to thr : histidine is a positively charged amino acid while threonine is a uncharged polar amino acid. Histidine also participates in charge relay system so this mutation will also affect the charge relay system of catalytic site of the enzyme.