### Enzyme Kinetics of Sphingosine KinaseSphingosine-1-phosphate (SPP) has recently been discovered to be important for cell survival. The synthesis of SPP from sphingosine and ATP is catalyzed by the enzyme sphingosine kinase. An understanding of the kinetics of the sphingosine kinase reaction may be important in the development of drugs to treat cancer. The velocity of the sphingosine kinase reaction was measured in the presence (5 μM) and absence of **threo-sphingosine**, a stereoisomer of sphingosine. The results are shown below. The sphingosine kinase used in all the reactions was 10 mg.#### Kinetic Data Table:| Sphingosine (μM) | v₀ (mg·min⁻¹) (no inhibitor) | v₀ (mg·min⁻¹) (with **threo-sphingosine**) ||------------------|-----------------------------|-----------------------------------------|| 2.5 | 32.3 | 7.6 || 3.5 | 40 | 10.5 || 5 | 50.8 | 14.6 || 10 | 72 | 25.4 || 20 | 87.7 | 43.9 || 50 | 115.4 | 70.8 |#### Analytical Questions:1. **What are the KM and VMAX in the presence and absence of the inhibitor?** - To determine the KM and VMAX, Michaelis-Menten plots or Lineweaver-Burk plots of the data would be used.2. **What kind of an inhibitor is threo-sphingosine? What is the KI value?** - Identify whether threo-sphingosine is a competitive, noncompetitive, or uncompetitive inhibitor by analyzing the impact on KM and VMAX. - KI value can be calculated using inhibitor kinetics equations.3. **What is the Kcat (turn over number)?** - The K<

For a one-substrate enzyme-catalyzed reaction, the Michaelis-Menton equation shows the quantitative…

Answered: Sphingosine-1-phosphate (SPP) has…

Biochemistry

9th Edition

ISBN:9781319114671

Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Chapter1: Biochemistry: An Evolving Science

Section: Chapter Questions

Problem 1P

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Interested in studying ethanol fermentation, you prepare two solutions of yeast extract that contains the cytosolic contents of Saccharomyces cerevisiae. You add glucose to both extracts at time zero, but to one (in red) you also add inorganic phosphate (added in two batches). Using a gas sensor, you monitor the CO2 generated by the two solutions over time and obtain the following data:
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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 =…
Given: Factor VIIa is a man-made protein analog to Factor VII, which is involved in coagulation. (Answer a, b, and c)a. Identify both a competitive and non-competitive inhibitor for Factor VIIa b. Draw a graph showing how both of these molecules will change the Velocity/[S] graph, and explain why this is the case. c. What would a graph look like if both inhibitors were added?
Hb Waterloo has an AspG1 (94)a to Gln mutation. Which of the following statements is TRUE? It has a high affinity for O2 because a hydrogen bond in the T state is broken. It has a low affinity for O2 because a hydrogen bond in the R state is broken. The Bohr effect is diminished due to the loss of the primary binding site of the Bohr proton. The mutant has a lower affinity for O2 due to the loss of a hydrogen bond present in the T state. Cooperativity in the mutant is increased because the mutation occurs in the switch region.
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