The final step in the pathway for the synthesis of glucose from lactate (gluconeogenesis) is: Glucose-6-phosphate H20 5 Glucose + Pi When glucose-6-phosphate is incubated with the proper enzyme and the reaction runs until equilibrium has been reached, the final concentrations are found to be: glucose-6-phosphate (0.035 mM), glucose (100 mM), and Pi (100 mM). Calculate AG°" at 25°C and pH 7.

The M and H subunits of lactate dehydrogenase have very similar sizes and shapes but differ in amino acidcomposition. If the only difference between the two were that theH subunit had a glutamic acid in a position where the M subunithad a serine, how would the five isozymes of LDH separate on electrophoresis using a gel at pH 8.6?

. The optimal conditions for salivary lysozyme (hydrolyzing glycoproteins of bacterial wall) are 37 C - temperature and pH is 5.2. Explain the decrease in this enzyme activity if the temperature will rise up to 60 °C and pH will be changed to 8.0. To answer the question: a) draw the graph of the velocity dependency on temperature and pH; b) calculate the relative enzyme activity if 10 mg of lysozyme catalyzes the formation of 5 uM of the product per 2 minutes. Concidor NH3: 5.

(b) You are investigating the effects of several agents on the activity of alcohol dehydrogenase. The enzyme activity data are shown in the table below. Construct a [substrate] vs. activity plot and a double-reciprocal plot for this enzyme. Be sure to label all axes. Determine the Vmax and KM for AD from the graphs in each type of plot. AD activity (nM/min) AD activity + agent A (nM/min) AD activity + agent B (nM/min) [Alcohol] (nM) 0.1 14 2 0.5 50 7 8. 1.0 65 10 30 2.0 72 12 45 4.0 80 14 62 8.0 85 15 75 32.0 90 16 90

1. Hydrolysis of 1 M glucose 6-phosphate catalyzed by glucose 6-phosphatase is 99% complete at equilibrium (i.e., 1% of the substrate remains). Which of the following statements is most nearly correct? (R= 8.315 J/mol-K; T = 298 K) A AG" is-11 kl/mol. B) AG" is +5 kJ/mol. C) AG" is 0 kJ/mol. DAG" is +11 kJ/mol. E) AG" cannot be determined from the information given. Explain your choice in one line: -2.16x298 (2) - 11386.15 -> 11.4 КТ 5 The high state conculto alle My negative and st" positive (either for D) then onditions, one

A solution of [U 14C] glucose-1-phosphate (specific activity = 16,000 cpm/mmole) was  incubated with glycogen and glycogen phosphorylase, an enzyme which adds glucose units on to  glycogen. Radioactivity was incorporated into the glycogen primer at a rate = 2550 cpm/min. The rate  of the enzymatic reaction in units of mmole glucose incorporated per minute is:  (a) 0.016 mmol/min  (b) 0.57 mmol/min  (c) 0.16 mmol/min  (d) 5.7 mmol/min

Calculcate Kcat for PNP substrate for both enzyme concentrations.  enzyme volume: 20 ul  Bovine Intensince Alkaline phosphatase molecular weight: 140,000 Bovine intenstine Alkaline phosphatase activity: 300 units/ml and 14 units/mg extinction coefficient PNP: 18.5 abs (mM-1 cm-1) Vmax: 0.332 moles/sec a) enzyme 1 concentration: undiluted b) enzyme 2 concentration: 1:1 dilution

8L.3.4

Pyruvate carboxylase catalyzes the first step of gluconeogenesis.   ATP + HCO3─ +  pyruvate  →   oxaloacetate + ADP + Pi   ∆G0’ = ─2.1 kJ mol-1   a) Calculate ΔG for this reaction under the following physiological conditions: 370C, pH 7      [pyruvate] = [HCO3─] = 4.0 mM      [oxaloacetate]= 2.0 mM      [ATP] = 3.5 mM      [Pi] = 5.0 mM      [ADP] = 1.8 mM

We want to measure the activity of alanine aminotransferase (ALAT) present in a serum. The reaction catalyzed by the enzyme is: Reaction 1: I- *H₂N- glutamate H - C-COO CH₂ CH₂ COO 0.1 M phosphate buffer pH 7.4 : 550 μL 1.2 M alanine: 100 μL CH3 pyruvate CH3 C time (min) A340 CIO O COO The enzyme reaction is alized in the following conditions: In a 1 cm-cuvette are added: COO™ pyruvate lactate dehydrogenase* (LDH, 300 µμg.mL-¹): 50 μL 1.5 mM NADH : 200 μL 0.04 M a-ketoglutarate: 500 µL serum containing ALAT: 600 μµL ALAT NADH + H+ 0 0.915 a-cétoglutarate COO LDH * Lactate dehydrogenase (LDH) reduces pyruvate into lactate, with the concomitant oxydation of NADH. This allows to indirectly measure the amount of product formed. с=0 CH₂ 1 0.741 Reaction 2: NAD+ CH₂ COO™ H-C CH3 OH COO™ lactate alanine H + *H3N-C The reaction is performed at 25 °C and the absorbance at 340 nm is monitored every minute, for 5 min. The absorbance values are given in the table below: Data: ENADH at 340 nm =…