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Trypsin has a peptide inhibitor called BPTI. Trypsin is still active without Ser195!!!!. If you mutate any of the three residues in the catalytic triad you still have an enzyme that is 10,000 fold faster than uncatalyzed rxn. How?. Transition State Stabilization. Metal-dependent protease.
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Trypsin is still active without Ser195!!!! If you mutate any of the three residues in the catalytic triad you still have an enzyme that is 10,000 fold faster than uncatalyzed rxn. How?
Transition State Stabilization
Binding energies of subsites - - - + - -
Transition state is half-chair conformation Use lactone as a transition state analog
Glucose + 2NAD+ + 2ADP + 2Pi 2pyruvate + 2NADH + 2ATP + 2H2O + 4 H+
Can be broken into 2 half reactions Glucose + 2NAD+ ∆Gº’1 = -146 kJ/mol 2pyruvate + 2NADH + 2H+
Can be broken into 2 half reactions 2ADP + 2Pi ∆Gº’2 = -61 kJ/mol 2ATP
∆Gº’1 = -146 kJ/mol ∆Gº’2 = -61 kJ/mol ∆G’ºs = ∆Gº’1 + ∆Gº’2 = -85 kJ/mol Under actual cellular conditions > 60% of the energy in glucose is recovered as ATP
Glucose + 6O2 ∆Gº’ = -2,840 kJ/mol 6CO2 + 6H2O There is much more energy left in pyruvate