Fe2+ in heme becomes oxidized to Fe3+ Essay Example for Free

Fe2+ in heme becomes oxidized to Fe3+ Essay Consumers associate bright red color with fresh meat and brownish tint to outdated, possibly spoiled meat no matter what the pull date says. Some vendors are treating the cut meat with CO before packaging in plastic wrap for supermarket meat counters. Why would this help sales? CO binds to oxygen binding site and this binding is not readily reversible. Hence Hemoglobin remains in ‘saturated’ form and appears red and fresh. This would definitely enhance sales. CH2OH 5. a. In the figure to the right, what type of bond links the two carbohydrate monomers together? Answer by checking in the spaces(s) provided below. OH Check all that apply; or check none of the above if none of the descriptions apply to the bond shown. _____ glycosidic bond _____ hemiketal bond _____ beta 1-6 linkage _____ester bond ____ ketal bond _____ a furanose bond _____ phosphodiester bond  ¬Ã‚ ¬_____ alpha 1-4 linkage _____ a pyranose bond _____ hemiacetal bond _____ alpha 1-6 linkage _____ none of the above_____ acetal bond _____ beta 1-4 linkage b. Is it possible that the figure shows part of glycogen? YES NO Explain. In your explanation, include at least two types of clues that give you the answer. For full credit, use precise terminology. No more than two sentences -one per clue are needed to answer this question. Glycogen is a polymer of ? -D-glucopyranose. It contains ? (1? 4) linkages and some ? (1? 6) links. 6. You are studying an enzyme that catalyzes the reaction turning substrate S into product P and obeys. Michaelis-Menton kinetics. You are conducting a series of enzyme assays to determine the Vmax of the enzyme: each successive assay uses the same amount of enzyme, but a different concentration of S. a. When the concentration of S is 10% of the Km, you measure a reaction velocity of 1 ? mole P produced per minute. What is the Vmax for the enzyme? Show all your work and include units at all steps. V= Vmax. [S]/KM+[S] V=1 ? mole/min 0. 1Km=S Vmax = V*(Km+[S])/[S] = 1*(Km+0. 1Km)/0. 1Km =1. 1/0. 1Km=0. 11Km The value of Vmax will be 0. 11 times the Michaelis-Menton constant for the given reaction. b. When you add a particular concentration of compound C to the reaction mixture of enzyme and substrate at 1/10 the KM, you find the product is produced at a much lower rate than when compound C is not present. However, if you repeat this experiment with the same concentrations of compound C and enzyme but a very high concentration of substrate, product is produced at about the same rate as the one you calculated in part ‘a’. Based on the evidence presented, compound C must be (please circle all that apply):a zymogen a competitive inhibitor an allosteric activator a non-competitive inhibitor an endergonic compound a transition state analog 7. Answer each question TRUE or FALSE. If you mark it false, provide a complete explanation of what is wrong with it. . a) Enzymes increase the stability of the product of a desired reaction by allowing ionizations, resonance and isomerization not normally available to substrates. ____TRUE ____ FALSE The reason this statement is false is: ionizations, resonance and isomerization increase the instability of the substrate. b) Lowering the affinity of hemoglobin for oxygen increases the effectiveness with which it delivers oxygen to the tissues, though it may decrease the amount of oxygen acquired in the lungs. ____TRUE ____ FALSE The reason this statement is false is: c) Whether the ? G for a reaction is larger, smaller or the same as ? G’0 depends on the concentrations of the compounds that participate in the reaction. ____TRUE ____ FALSE The reason this statement is false is: d) Enzymes are potent catalysts because they drive reactions to completion while other catalysts drive reactions to equilibrium. ____TRUE____ FALSE. The reason this statement is false is: catalyst lowers the energy barrier to a reaction, increases the fraction of molecules that have enough energy to attain the transition state and hence make the reaction go faster in both directions. e) The hydrolysis of ATP has a large negative ? G’0, nevertheless it is stable in solution due to the ionization of the phosphates. ____TRUE ____ FALSE The reason this statement is false is: f) L-Malate + NAD+ - oxaloacetate + NADH + H+ ? G’0 = +29. 7 kJ/mol The reaction as written may occur in some cells at some concentrations of substrate and product. ____TRUE ____ FALSE The reason this statement is false is: this is a step in the Kreb’s cycle and occurs in all respiring cells. g) Linking the endergonic reaction X -Y to a second, energetically favorably reaction Y-Z will shift the equilibrium constant of the first reaction. ____TRUE ____ FALSE The reason this statement is false is: h) Non-covalent interactions are too weak to influence the three-dimensional structure of macromolecules. ____ TRUE ____ FALSE The reason this statement is false is: Tertiary structure is basedon non-covalent interactions. i) Starch and glycogen are both polymers of ? -D-glucose. ____TRUE ____ FALSE The reason this statement is false is: they are ? -D-glucopyranose polymers. j) Enzymes bind a transition state intermediate such that it cannot be converted back to substrate. ____TRUE ____ FALSE The reason this statement is false is: k) When the reactants and products are all in equal concentrations, no further change in concentration will take place. ____TRUE ____ FALSE The reason this statement is false is: l).The rate of migration of a protein through an SDS-polyacrylamide gel is not influenced by the charge of the protein. ____TRUE. ____ FALSE The reason this statement is false is; m) In general, when ATP hydrolysis is coupled to an energy-requiring reaction, the actual reaction often consists of the transfer of a phosphate group from ATP to another substrate, rather than the actual hydrolysis of ATP ____TRUE ____ FALSE The reason this statement is false is: 8. Downugo, a marketed drug widely used by diabetics with hypertension, is metabolized by the liver enzyme CYP3A4. Your company is developing an insulin mimetic. You have three promising candidate compounds, all of which are metabolized by CYP3A4. The table below shows the KD of the binding of the molecule to the insulin receptor and the IC50 for each compound as a competitor for Downugo metabolism by CYP3A4. Compound KD for insulin receptor IC50 for CYP3A4 vs Downugo A 10? M 8 mM B 10 nM 50 nM C 5 nM 200 nM Your company has the resources to take only one compound into further development. Based on these results, which is your selection? Explain briefly. A. Very low quantities should be required for binding with insulin receptor, but the IC50 values must also be higher.