Which of the following statements is false for the
catalyticmechanism in serine proteases like chymotrypsin?
1. theinitial proton transfer makes an 'incipient' alkoxide ion,
which isa better nucleophile than an alcohol.
2. the initialbond formation in the covalent intermediate is
between the serine oand carbonyl c in the peptide backbone.
3. his actsinitially as a general acid catalyst, providing a proton
to thecarbonyl oxygen of the substrate.
4. prior tobinding the peptide substrate, the active site of the
restingenzyme contains a serine residue, a deprotonated histidine
and adeprotonated aspartic acid residue.
5. the oxyanionhole stabilizes the anionic tetrahedral intermediate
by having twoh-bond donors at the right location, poised to
interact with thenegative charge.