Calculate ΔG° and K at 25°C for the following reaction.

Chymotrypsin is an enzyme that is optimized to function in the small intestine (at a pH of ~7.4). Explain, given what you know about the chymotrypsin mechanism and what we learned about acid/base chemistry, why chymotrypsin would not be able to initiate catalysis if it were secreted into the stomach (pH ~2.5).

Explain the difference between ΔG°’ and ΔG and calculate the free energy (delta G) of hydrolysis of ATP in a rat liver cell in which the ATP, ADP, and Pi concentrations are 3.4, 1.3, and 4.8 mM.

From a kinetics experiment, the Vmax was determined to be 450µM∙min-1.  For the kinetic assay, 0.1mL of a 0.05mg/mL solution of enzyme was used, and the enzyme has a molecular weight of 125,000 g/mole.  Assume a reaction volume of 700µL.  Calculate the kcat  (in sec-1) for the enzyme.

A particular reaction has a ΔG‡ of 30.0 kJ mol-1 at 25.0 °C. In the presence of an enzyme, the same reaction has a ΔG‡ of 1.50 kJ mol-1 at the same temperature. Calculate the rate enhancement of this enzyme. (R = 8.3145 J mol-1 K-1)

A one-to-one protein (P)-ligand (L) complexation (P + L PL) has a dissociation equilibrium constant (Kd) value of 100 nM at 25°C, and the Kd remains the same at 37°C. 1) What is AS of binding at 25°C? Assume ACp of the binding is 0 over the temperature range. AS = 1.34E2 kJ/(mol*K) (note the unit!!) (sig. fig =3) 2) What is the concentration of the PL complex formed at equilibrium when you mix 0.20 uM (microM) of Protein and 1.0 uM of Ligand together at 37°C? PL at equilibrium = 8.1E-1 uM (note the unit!!) (sig. fig =2)

For a Michaelis-Menten reaction, k₁=5 x 107/M-s, k-1-2 x 104/s, and k2=4 x 10²/s. Calculate the Ks and KM for this reaction. Does substrate binding achieve equilibrium or steady state?

Intramitochondrial ATP concentrations are about 5 mM, and phosphate concentration is about 10 mM. Consider that ADP is five times more abundant than AMP.   a. Calculate the molar concentrations of ADP and AMP at an energy charge of 0.85.   b. Calculate ∆G' for ATP hydrolysis under these conditions (∆G0' for ATP hydrolysis is -32.2 kJ/mol)       The energy charge is defined as ( [ATP] + 1/2 [ADP] ) / ( [ATP] + [ADP] + [AMP] )

Given the initial rate data for the reaction A + B → C, determine the rate expression for the reaction. [A], M [B], M A[C]/At (initial) M/s 0.0418 0.122 2.73 x 10-4 0.0836 0.122 10.9 × 10 4 0.0418 0.488 2.73 x 104 O A[C] At ○ A[C] ΔΙ = 0.439 Ms[A][B]² = 1.27 M²s¹ [A][B] ● A[C] = 6.53 × 10³ s¹ [A] At O A[C] = 0.156 M's¹[A]² At ○ A[C] At = 5.35 x 102 M2s[A][B]

The typical Michaelis-Menten equation mathematically describes the overall rate of the reaction as V (this is because biologists don't like math). What does V actually mean? (write the definition of V in differential equation form). V= d( )/dt Reaction rate Substrate concentration V max ·½V TURK