3. One indication of the relative importance of various ATP-producing pathways is the Vmax of certain enzymes of these pathways. The values of Vmax of several enzymes from the pectoral muscles (chest muscles used for flying) of pigeon and pheasant are listed below. Vmax (umol substrate/min/g tissue) Pigeon Enzyme Pheasant Hexokinase 3.0 2.3 120.0 Glycogen phosphorylase Phosphofructokinase-1 Citrate synthase Triacylglycerol lipase 18.0 24.0 143.0 100.0 15.0 0.07 0.01

3. One indication of the relative importance of various ATP-producing pathways is the Vmax of certain enzymes of these pathways. The values of Vmax of several enzymes from the pectoral muscles (chest muscles used for flying) of pigeon and pheasant are listed below. Vmax (umol substrate/min/g tissue) Pigeon Enzyme Pheasant Hexokinase 3.0 2.3 120.0 Glycogen phosphorylase Phosphofructokinase-1 Citrate synthase Triacylglycerol lipase 18.0 24.0 143.0 100.0 15.0 0.07 0.01

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter27: Metabolic Integration And Organ Specialization

Section: Chapter Questions

Problem 20P: Figure 27.3 illustrates the response of R (ATP-regenerating) and U (ATP-utilizing) enzymes to energy...

See similar textbooks

Similar questions

The formation of glutamine from glutamate and ammonium ions requires 14.2 kJ mol-1 of energy input. It is driven by the hydrolysis of ATP to ADP mediated by the enzyme glutamine synthetase. {a) Given that the change in Gibbs energy for the hydrolysis of ATP corresponds to ΔG = -31 kJ mol-1, under the conditions prevailing in a typical cell , can the hydrolysis drive the formation of glutamine? (b) What amount {in moles) of ATP must be hydrolysed to form 1 mol glutamine? (c) Suppose that the radius of a typical cell is 10 μm and that inside it 106 ATP molecules are hydrolysed each second. What is the power density of the cell in watts per cubic metre (1W = 1 Js- 1)? (d) A computer battery delivers about 15 Wand has a volume of 100 cm3 Which has the greater power density, the biological cell or the battery?
When enzyme solutions are heated, there is a progessive loss of catalytic activty over time due to denaturation of the enzyme. A solution of the enzyme hexokinase incubated at 45 degrees Celsius lost 50% of its activity in 12 minutes, but when incubated at 45 degrees Celsius in the presence of a very large concentration of one of its substrates, it lost only 3% of its activity in 12 minutes. Suggest why thermal denaturation of hexokinase was retarded in the presence of one substrates.
ATP is a (+) allosteric effector, and CTP is a (-) allosteric effector of theenzyme ATCase. Both of these heterotropic effectors bind to the regulatorysubunits on ATCase. The substrates of ATCase, aspartate and carbamoylphosphate, bind the enzyme active site with positive cooperativity (i.e.,they exert a “+” homotropic effect on activity). As the concentrations ofthe substrates change from values where [S] ≪ KM to values where [S] issaturating ([S]≫ KM), how will the binding constants for each of the twoallosteric effectors change? In other words, does ATP bind ATCase withhigher affinity when [S] is low or high? Does CTP bind ATCase with higheraffinity when [S] is low or high?
The catalytic efficiency of many enzymes depends on pH. Chymotrypsin, which has a well-known catalytic mechanism, shows a maximum value of kcat/Km at pH 8.0. A) Draw a pH curve of chymotrypsin activity over the pH range of 5 to 10 and briefly explain the rationale within the context of catalysis for your depiction. In particular, note how kcat and Km may change over this pH range. B) Enzymes of the a-amylase family catalyze a reaction by forming a covalent intermediate analogous to chymotrypsin, but to a conserved aspartate residue. Illustrate a catalytic mechanism containing a tetrahedral intermediate for a glycogen debranching enzyme based upon its potential membership in the a-amylase family. (don’t need to draw a whole glycogen)
1) Sketch out the schematic diagram for the enzymatic mechanism of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) Please provide the structure of the functional groups of the substrate and enzyme involved in the reaction at each step (rest of the structure can be indicated as R) Indicate clearly the flow of the electrons at each step Indicate in short form the cofactor involved and the acid or basic groups of the enzyme involved
When enzyme solutions are heated, there is a progressive loss of catalytic activity over time due to denaturation of the enzyme. A solution of the enzyme hexokinase incubated at 450C lost 50% of its activity in 12 minutes, but when incubated at 450C in the presence of a very large concentration of one of its substrates, it lost only 3% of its activity in 12 minutes. Suggest why thermal denaturation of hexokinase was retarded in the presence of one substrates
When enzyme solutions are heated, there is a progressive loss of catalytic activity over time due to denaturation of the enzyme. A solution of the enzyme hexokinase incubated at 45 °C lost 50% of its activity in 12 min, but when incubated at 45 °C in the presence of a very large concentration of one of its substrates, it lost only 3% of its activity in 12 min. Suggest why thermal denaturation of hexokinase was retarded in the presence of one of its substrates.
The oxidation of glucose to CO2 and water is a major source of energy in aerobic organisms. It is a reaction favored mainly by a large negative enthalpy change. C6H12O6(s) + 6O2(g) →6CO2(g) + 6H2O(l) ∆H° = -2816 kJ/mol ∆S ° = +181 J/mol . K (a) At 37 °C, what is the value for ∆G°? (b) In the overall reaction of aerobic metabolism of glucose, 32 moles of ATP are produced from ADP for every mole of glucose oxidized. Calculate the standard state free energy change for the overall reaction when glucose oxidation is coupled to the formation of ATP at 37 °C. (c) What is the efficiency of the process in terms of the percentage of the available free energy change captured in ATP?
Consider the complete oxidation of one mole of simple TAG containing behenic acid residues (22:0). I. For one mole of the fatty acid residue, determine the following: a. ATP yield obtained from the oxidation of acetyl CoA entering the TCA cycle and ETC b. ATP yield obtained from NADH coming from the complete β-oxidation of the fatty acid residue c. ATP yield obtained from FADH2 coming from the complete β-oxidation of the fatty acid residue d. net ATP yield of ATP in the complete oxidation of the fatty acid residue II. What is the net ATP yield for the complete oxidation of all the fatty acid residues of the simple TAG? (Note: glycerol backbone is not included)
Compare and contrast Pyruvate Dehydrogenase with a-ketoglutarate dehydrogenaseOutline the mechanisms of both enzymes. Discuss the functions of the coenzymes. List the similarities and the differences between the 2 enzymes. Both are very large membrane bound complexes. What are the advantages of this strategy?How detailed is the enzyme structure known below(It's Pyruvate Dehydrogenase )? What insight(s) does this structural detail give you about the enzyme mechanism.
2 The following strain of cells lack one enzyme in metabolic pathway. Which of the following strain can grow on glucose under both aerobic and anaerobic conditions, although it grows slower than normal cells under aerobic condition? Explain (less than 100 words). A strain: lack glyceraldehyde-3-phosphate dehydrogenase B strain: lack lactate dehydrogenase C strain: lack pyruvate dehydrogenase
Consider the complete oxidation of one mole of simple TAG containing behenic acid residues (22:0). I. For one mole of the fatty acid residue, determine the following: a. ATP yield obtained from the oxidation of acetyl CoA entering the TCA cycle and ETC b. ATP yield obtained from NADH coming from the complete β-oxidation of the fatty acid residue c. ATP yield obtained from FADH2 coming from the complete β-oxidation of the fatty acid residue