If chymotrypsin molecule undergoes a ser-195-ala mutation then :
Serine- 195 is a highly reactive residue of chymotrypsin molecule.It endows chymotrypsin with its 'Reactivity' and not its ability to bind to substrate. In absence of Ser- 195 residue, chymotrypsin is inactivated i.e., it will not cleave, however, it still has the ability to bind (by viue of other remaining residues).