2. The effect of pH on enzyme activity. Reaction rate pH 1.0 8.5 10.0 1.5 2.0 8.5 2.5 3.0 7.0 5.5 3.5 3.0 a. “DRAW A LINE GRAPH OF THE RESULTS OF THE EFFECTS OF pH ON THE ENZYME PEPSIN'S REACTION RATE.’ b.WHY DO YOU THINK IT WORKS BEST AT SUCH AN ACIDIC pH?

15) The graph at right shows the results of reaction rate vs. substrate concentration for a Michaelis-Menten type enzyme 16) Th a. True b. False* reaction rate substrate concentration

V 23. The graph below is a graph of Vmax (a) Label the graph clearly with both the Vmax and the Km. Estimate the Km from this graph giving the correct units. v/Vmax 1.0 0.5 0.0 0.0 vs [S] for an enzyme. Enzyme Activity vs [Substrate] :0.2 0.4 Substrate (HM): 0.6 (b) If the Vmax = 25 mmoles per minute per µmole of enzyme calculate the Keat and the specificity constant."

4. a. Calculate the KM (Michaelis constant) and the vmax (the maximum initial rate) for both substrates (sphingosine and ATP). Show your work, and be careful about units. b. threo-dihydrosphingosine, a stereoisomer of sphingosine, is an inhibitor of sphingosine kinase. What kind of inhibitor (competitive, uncompetitive, noncompetitive) is threo-dihydrosphingosine? Citing information from the Lineweaver-Burke plots, explain how you can tell.

Select all FALSE statements about allosteric enzymes.  a. They interconvert between a more active form and a less active form. b. They tend to have a hyperbolic curve of ?0 vs. [S]. c.They conform to Michaelis–Menten kinetics. d. They are generally small single subunit proteins. e. They may have binding sites for regulatory molecules that are separate from active sites.

1. The concentration of substrate X is high. What happens to the rate of the enzyme-catalyzed reaction if the concentration of substrate X is reduced? Explain. 2. An enzyme has an optimum pH of 7.2. What is most likely to happen to the activity of the enzyme if the pH drops to 6.2? Explain

1a.Sketch a graph that shows an enzyme that functions at an optional pH of b. which organ of the body does it likely to work at? 2. On the same graph from la, sketch another line/curve that shows what happen to the enzyme activity (in #1a) if a constant [ ] of inhibitors is added.

Part 1: Assess the following partial results section below by editing it for brevity by omitting any unnecessary parts (1 point), explain why you decided to remove certain sections (1 point): To evaluate inhibitory effects of the selected molecules, 10mM stock solutions of each molecule were prepared in DMSO. A reaction mixture (200μl) was prepared with the same formula optimized for the enzyme activity assay (0.1 M Tris-HCl ph 8, 0.1 M KCI, 25 mM NaCl, 0.25 mM ATP, and two units of inorganic yeast pyrophosphatase) with 10 µM of the sample molecule. The reaction mixture was incubated for 20 minutes at ambient temperature. Enzymatic reaction was triggered by addition of the substrate B (0.2 mM) and the absorbance of the product was monitored at 290 nm for 10 minutes. Six out of 15 sample molecules showed appreciable inhibition at 10 μM (Figure 5). Three of the molecules, A3, A6, and A7 exhibited more than 50% inhibition of the enzyme activity and were further diluted to find the minimal…