What type of functional group might be responsible for the pH effect on kcat? Justify your answer based on the "generic" pKa values of functional groups in peptides and proteins.
1) Cysteine with a thiol group, tyrosine possessing an aromatic hydroxy (OH) group with an unusually low pKa or histidine having imidazole group with an unusually high pKa. And so on if the unusual pKa is noted.
