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Chapter 10: Regulatory Strategies: Enzymes and Hemoglobin
Chapter 10: Regulatory Strategies: Enzymes and Hemoglobin
- Chapter 10 is about the regulation of function.
- Allosteric control, isozymes, reversible covalent modification, and proteolytic activation are some of the regulatory mechanisms discussed.
- The authors used examples to show the structure-function relationships involved in the control mechanisms.
- The first step in the synthesis of pyrimidine is the condensation of carbamoylphosphate and aspartate.
- Its activity is regulated both positively and negatively.
- The ability to efficiently transport oxygen in blood and release it to myoglobin is dependent on coorperative binding of oxygen to hemoglobin.
- Hb is regulated by H+, CO2, and 2,3-biphosphoglycerate.
- After the section on allosteric control, the authors show how isozymes can be used to regulate enzymes in a tissue specific manner.
- The authors talk about the regulation of enzymes with modifications such as acetylation and ubiquination.
- The authors use the example of the cAMP dependent protein kinase (PKA) as an example of how a target can be regulated.
- The authors turn to proteolytic cleavage.
- The active forms of chymotrypsin, trypsin, and pepsin come from their inactive zymogens.
- Chapter 9 presented the mechanisms of action.
- The authors conclude Chapter 10 with a discussion of the blood clotting cascade, a series of proteolytic activations of clotting factors that lead to the formation of fibrin clot.
- The proteolytic enzymes are linked to several stimulating and inhibiting proteins.
- You should be able to complete the objectives once you have mastered this chapter.
- List the four major regulatory mechanisms that control activity.
- Give examples of ways in which a given isozyme can be different.
- List the modifications used to regulate the activity of the proteins.
- Phosphory is an effective control mechanism.
- Examples of zymogens and their biological processes can be given.
- A shift to curve B could be caused by the addition of an irreversible inhibitor.
- Homotropic activation is the allosteric effect of CTP.
- The allosteric effects that result from the interaction of hemoglobin with O2, CO2, H+, and BPG are reflected in the oxygen dissociation curve for hemoglobin.
- A phosphoryl group is transferred from oneprotein to another.
- There is a human being that is activated by a molecule.
- The source of trypsin is the pancreas.
- The chymotrypsinogen needs the cleavage of at least two bonds by trypsin.
- The zymogens are listed in the left column and the enzymes are listed in the right column.
- An allosteric inhibition is involved in the inactivation of trypsin.
- When the synthesis of pyrimidine nucleotides is available, the activation of ATCase occurs.
- The overproduction of pyrimidine nucleotides is prevented by feedback inhibition.
- a, c, d 7.
- Fetal hemoglobin is composed of different parts than adult hemoglobin.
- Fetal hemoglobin's affinity for oxygen is higher, and the fetus can extract O2 from maternal blood.
- The change in the environment of His 146 increases its affinity for protons because of the attraction between the negative charge of the aspartate and the protons.
- Two negative charges are introduced to a phosphoryl group.
- A phosphoryl group can form hydrogen bonds to adjacent H-bond partners.
- Local effects can be transmitted to more distant parts of theprotein in a similar way toosteric effects.
- Because trypsin is the common activator of the zymogens, it will produce the carboxyl-terminal residues.
- Ca2+ is chelators of g-carboxyglutamate.
- The elec trostatic anchor is Ca2+ and it brings interdependent clotting factors into close proximity.
- A study was conducted to understand the mechanism of the allosteric transi tion in ATCase.
- The nitrotyrosine reporter group was contained in the modified catalytic subunits.
- The first step in the biosynthetic pathway leads to the synthesis of cytidine triphosphate.
- When the cell has an ample supply of CTP, it shuts off the biosynthetic pathway.
- The first step in a pathway may not be the main regulatory step.
- The investigation of the properties of ATCase has been done with the use ofphosphonacetylL-aspartate.
- An effective respiratory carrier needs to be able to pick up oxygen from the lungs.
- Patients suffering from pneumonia have a portion of their lungs filled with fluid, and therefore have reduced lung surface area available for oxygen exchange.
- Standard hospital treatment of these patients involves placing them on a ventilating machine set to deliver enough oxygen to keep their blood pressure under control.
- Predict if each of the following sequence is likely to be phosphorylated.
- Explain your answers and tell which one would be phosphorylated.
- The steady-state [B]/[A] ratio can be increased by an increase in intracellular cAMP levels.
- Trypsin's primary structure has 13 and 2 arginine residues.
- Although thrombin has many properties in common with trypsin, the conversion of prothrombin to thrombin is not autocatalytic.
- Direct Chem ical measurements can't be used to determine if the factors are within normal concentrations or deficient because many of them are present in small concentrations.
- If a deficiency has been established, the affected person's blood can be used to screen for it in other people.
- A deficiency in Factor XII prolongs the time it takes to clot.
- If you have blood from someone who has a Factor XII deficiency, you should design a test that can help determine if another person has a Factor XII deficiency.
- Reactions that are far from equilibrium are the ones that are irreversible in cells.
- Amplification cascades are important in a number of regulatory processes.
- There is a catalyst for the activation of the enzyme B.
- Each pathway has a turnover number of 103.
- Both thrombin and trypsin are serine proteases that can leave the bond on the carboxyl side of arginine.
- The system would behave like a single form if the R and T forms were equal in affinities.
- The plot of the reaction speed versus the concentration would be hyperbolic.
- The aim of the experiment was to show that the reporter group undergoes a change in its structure because it is bound to a different part of the enzyme.
- If the experiment was to give meaningful results, binding of the substrate to the reporter group had to be stopped.
- There would be no control over the production of X from B if regulation were to occur at step 1 only.
- There would be no regulation over the production of X from A if only step 2 were regulated.
- Control of the amount of X produced from both A and B is provided by regulation at step 3.
- The main regulatory step is usually after the branch point.
- PALA is a bisubstrate analog, that is, it resembles a combination of both substrates, and it is a transition state analog for the carbamoylphosphate-aspartate complex.
- The location of the active site has been revealed by the X-ray analysis of ATCase.
- Comparisons of structures with and without PALA have shown the large structural changes that ATCase undergoes.
- The active site of ATCase is an analog of PALA.
- At low concentrations, the distribution of ATCase molecule to the R is shifted.
- This increases the activity of the enzyme.
- BPG interacts with hemoglobin.
- The interaction between the negatively charged phosphates of BPG and the positively charged residues of hemoglobin is stronger in the interior environment than it would be on the surface.
- The force of interactions is proportional to the medium's dielectric constant.
- It is possible that the dielectric constant is as low as 2.
- The surface has a dielectric constant of 80, but the electrostatic interactions there are much more stable.
- Substance A wouldn't let oxygen into peripheral tissues.
- Oxygen wouldn't be loaded in the lungs with Substance B.
- An effective carrier has an oxygen dissociation curve between substance A and substance B.
- It would have a lot of oxygen in the lungs and less in the peripheral tissues.
- Administering enough oxygen to give saturation levels greater than 92 would be wasteful because one reaches the point of diminishing returns.
- The risk of compromising oxygen delivery to the tissues is caused by giving oxygen in amounts less than required.
- According to the model, a mixture of fully oxygenated and fully deoxygenated molecules is posed with all of the components in the R form.
- According to the sequential model, some of the molecule's parts are oxygenated in the R form and others are deoxygenated in the T form.
- There is a consensus that the Arg-Arg-X-Ser-Z is large and small.
- The site is either Ser or Thr.
- The activity of en zyme 1 should be decreased by phosphorylation.
- The steady-state ratio of [B]/[A] could be increased by an increase in cAMP levels.
- The control of opposing metabolic sequence is observed frequently in cells.
- The activation of trypsinogen is an autocatalytic process.
- trypsinogen can be cleaved as the process occurs.
- The activation of chymotrypsinogen corresponds to Curve II.
- The chymotrypsinogen is not autocatalytic.
- Tryspin can convert chymotrypsinogen to p-chymotrypsin.
- The time course is initially linear.
- The active site of trypsin needs to be partially buried.
- Thrombin cleaves bonds.
- When pro thrombin is converted to thrombin, there are two bonds that are broken.
- The conversion cannot be autocatalytic.
- Prepare two blood samples for testing.
- Factor XII deficiency is probably not involved if clotting time is restored to normal.
- Factor XII deficiency can be suspected if the addition of normal plasma restores normal time but the addition of Factor XII deficiency does not.
- The reaction is at equilibrium.
- Nothing would happen if the reaction was made more active.
- The reaction is still at equilibrium.
- If the reaction is displaced far from equilibrium, more product will be produced.
- If a regulatory enzyme is to increase the flux rate through a pathway, it must make an irreversible step.
- One molecule of active A will lead to the activation of more than one molecule of D. 103 molecule of active B will be produced by Active A.
- Each of the 103 molecule of active B will make 103 molecule of C. The total of active C and B is 106 and 103, respectively.
- Both thrombin and trypsin have an oxyanion hole at the active site.
- Both sites have a negatively charged pocket that can be binding.
- thrombin has enough space to accommodate a Gly residue next to the Arg binding site in contrast to trypsin, which has no restrictions as to the amino acid residue that can be accommodated at the corresponding position.
- The positive charge on the carbonyl oxygen in the transition state is thought to be stable by histidine 134.
- Whether one proceeds R - T -TS or R -RSTS, S is the same.
- The constant for the conversion of R to T and R toRS is 103.
- The constant for the conversion of T toTS is 10 since the affinity of R for S is 100 times that of T. The constant for the conversion ofRS toTS is 10.
- The R to T ratio is changed by the binding of the substrate with a hundredfold tighter binding to R.
- The ratio in the fully liganded molecule will be 10 if there is no substrate.
- L is the ratio of T to R in the sence of ligand, and L is the number 105.
- The fraction of the molecule in the R state is either [R]/([R] + [T]) or [R]/([R] + [R]Lj).
- The concerted model can't be counted for negative cooperativity due to the fact that the binding of substrate promotes a conformational transition of all subunits to the high-affinity R state.
- If the model holds, allosteric interactions must be cooperative.
- In the sequential model, the binding of ligand changes the structure of the subunit to which it is bound, but not that of its neighbors.
- The binding of PALA ATCase switches from the T to the R state.
- There are fewer free catalytic sites for an empty molecule than there are for a bound one.
- The R state of the PALA- containing enzyme makes it more affinity for the substrates.
- The binding affinities of the R and T states are for the analog.
- All of the time, the R state would be occupied by the Mutant enzyme.
- According to a classical saturation curve, the reaction rate depends on the fraction of active sites occupied by the substrate.
- A molecule with a high density of negative charge is needed to replace 2,3-BPG.
- The best candidate is (b) inositol hexaphosphate, an analogue of a major natural hemoglobin effector.
- The zymogens are activated by the cleavage of one or more bonds.
- The pepsin moities are hydrolyzed when the catalytic site is exposed.
- The time required for half the pepsinogen molecule to be activated is dependent on the number of molecules present.
- A mixture of the two bloods will not clot if both patients have a Factor VIII deficiency.
- If the second patient's bleeding disorder is caused by the deficiency of another factor, a mixture of the two bloods should clot.
- Factor X is used to convert prothrombin to thrombin on blood platelets.
- The proteolytic activation removes the fragment of prothrombin that contains Ca+2-binding sites and releases thrombin.
- Factor X can be activated by other prothrombin molecule if it remains bound to the platelets.
- It is thought that antithrombin III is not good for thrombin.
- Many en zyme inhibitors have high affinity for active sites.
- Thrombin can react with antithrombin III because it has a fully formed active site.
- Chapter 3 of your textbook introduces a coiled coil.
- Since this is a long molecule made up of repeating units, one would expect to see side chains at regular intervals.
- The binding of elastase by a1-antitrypsin is dependent on the side chain of methionine 358, which is most susceptible to oxidation by cigarette smoke.
- A side chain with a strong binding affinity for elastase is needed.
- The side chain of leucine is more stable than the side chain of methionine but has the same volume.
- The sequential model predicts that the fraction in the R state should be equal to the fraction in the Y.
- A conformational change in response to a distant site is reported by the change in the absorbance.
- The structure of a different trimer that carries the reporter nitrotyrosine group is altered by the binding of succinate to the active sites of a native trimer.
- Allosteric activators drive the catalytic subunits into the active state.
- The effect of CTP is to drive the catalytic subunits into an inactive state and decrease the absorbance.
- The effect is working here.
- The valine side chain on the surface tries to avoid water by making favorable van der Waals interactions with the leucine and phenylalanine side chains.
- The effect is to cause long fibers to crystallize and distort the shapes of red blood cells.
- In step 1, the aspartate smino group carries out a nucleophilic attack on the carbonyl carbon.
- The negatively charged oxyanion can be mitigated by the histidine in the active site.
- The serine- OH group takes the role of water and accepts the g-phosphate in the reaction.
- During the attack on the g-phosphate in step 1, the active site will need a group to accept the protons from the serine oxygen.
- The extra negative charge on the intermediate between steps 1 and 2 would be stable if there was a functional group at the active site.
Chapter 10: Regulatory Strategies: Enzymes and Hemoglobin
- Chapter 10 is about the regulation of function.
- Allosteric control, isozymes, reversible covalent modification, and proteolytic activation are some of the regulatory mechanisms discussed.
- The authors used examples to show the structure-function relationships involved in the control mechanisms.
- The first step in the synthesis of pyrimidine is the condensation of carbamoylphosphate and aspartate.
- Its activity is regulated both positively and negatively.
- The ability to efficiently transport oxygen in blood and release it to myoglobin is dependent on coorperative binding of oxygen to hemoglobin.
- Hb is regulated by H+, CO2, and 2,3-biphosphoglycerate.
- After the section on allosteric control, the authors show how isozymes can be used to regulate enzymes in a tissue specific manner.
- The authors talk about the regulation of enzymes with modifications such as acetylation and ubiquination.
- The authors use the example of the cAMP dependent protein kinase (PKA) as an example of how a target can be regulated.
- The authors turn to proteolytic cleavage.
- The active forms of chymotrypsin, trypsin, and pepsin come from their inactive zymogens.
- Chapter 9 presented the mechanisms of action.
- The authors conclude Chapter 10 with a discussion of the blood clotting cascade, a series of proteolytic activations of clotting factors that lead to the formation of fibrin clot.
- The proteolytic enzymes are linked to several stimulating and inhibiting proteins.
- You should be able to complete the objectives once you have mastered this chapter.
- List the four major regulatory mechanisms that control activity.
- Give examples of ways in which a given isozyme can be different.
- List the modifications used to regulate the activity of the proteins.
- Phosphory is an effective control mechanism.
- Examples of zymogens and their biological processes can be given.
- A shift to curve B could be caused by the addition of an irreversible inhibitor.
- Homotropic activation is the allosteric effect of CTP.
- The allosteric effects that result from the interaction of hemoglobin with O2, CO2, H+, and BPG are reflected in the oxygen dissociation curve for hemoglobin.
- A phosphoryl group is transferred from oneprotein to another.
- There is a human being that is activated by a molecule.
- The source of trypsin is the pancreas.
- The chymotrypsinogen needs the cleavage of at least two bonds by trypsin.
- The zymogens are listed in the left column and the enzymes are listed in the right column.
- An allosteric inhibition is involved in the inactivation of trypsin.
- When the synthesis of pyrimidine nucleotides is available, the activation of ATCase occurs.
- The overproduction of pyrimidine nucleotides is prevented by feedback inhibition.
- a, c, d 7.
- Fetal hemoglobin is composed of different parts than adult hemoglobin.
- Fetal hemoglobin's affinity for oxygen is higher, and the fetus can extract O2 from maternal blood.
- The change in the environment of His 146 increases its affinity for protons because of the attraction between the negative charge of the aspartate and the protons.
- Two negative charges are introduced to a phosphoryl group.
- A phosphoryl group can form hydrogen bonds to adjacent H-bond partners.
- Local effects can be transmitted to more distant parts of theprotein in a similar way toosteric effects.
- Because trypsin is the common activator of the zymogens, it will produce the carboxyl-terminal residues.
- Ca2+ is chelators of g-carboxyglutamate.
- The elec trostatic anchor is Ca2+ and it brings interdependent clotting factors into close proximity.
- A study was conducted to understand the mechanism of the allosteric transi tion in ATCase.
- The nitrotyrosine reporter group was contained in the modified catalytic subunits.
- The first step in the biosynthetic pathway leads to the synthesis of cytidine triphosphate.
- When the cell has an ample supply of CTP, it shuts off the biosynthetic pathway.
- The first step in a pathway may not be the main regulatory step.
- The investigation of the properties of ATCase has been done with the use ofphosphonacetylL-aspartate.
- An effective respiratory carrier needs to be able to pick up oxygen from the lungs.
- Patients suffering from pneumonia have a portion of their lungs filled with fluid, and therefore have reduced lung surface area available for oxygen exchange.
- Standard hospital treatment of these patients involves placing them on a ventilating machine set to deliver enough oxygen to keep their blood pressure under control.
- Predict if each of the following sequence is likely to be phosphorylated.
- Explain your answers and tell which one would be phosphorylated.
- The steady-state [B]/[A] ratio can be increased by an increase in intracellular cAMP levels.
- Trypsin's primary structure has 13 and 2 arginine residues.
- Although thrombin has many properties in common with trypsin, the conversion of prothrombin to thrombin is not autocatalytic.
- Direct Chem ical measurements can't be used to determine if the factors are within normal concentrations or deficient because many of them are present in small concentrations.
- If a deficiency has been established, the affected person's blood can be used to screen for it in other people.
- A deficiency in Factor XII prolongs the time it takes to clot.
- If you have blood from someone who has a Factor XII deficiency, you should design a test that can help determine if another person has a Factor XII deficiency.
- Reactions that are far from equilibrium are the ones that are irreversible in cells.
- Amplification cascades are important in a number of regulatory processes.
- There is a catalyst for the activation of the enzyme B.
- Each pathway has a turnover number of 103.
- Both thrombin and trypsin are serine proteases that can leave the bond on the carboxyl side of arginine.
- The system would behave like a single form if the R and T forms were equal in affinities.
- The plot of the reaction speed versus the concentration would be hyperbolic.
- The aim of the experiment was to show that the reporter group undergoes a change in its structure because it is bound to a different part of the enzyme.
- If the experiment was to give meaningful results, binding of the substrate to the reporter group had to be stopped.
- There would be no control over the production of X from B if regulation were to occur at step 1 only.
- There would be no regulation over the production of X from A if only step 2 were regulated.
- Control of the amount of X produced from both A and B is provided by regulation at step 3.
- The main regulatory step is usually after the branch point.
- PALA is a bisubstrate analog, that is, it resembles a combination of both substrates, and it is a transition state analog for the carbamoylphosphate-aspartate complex.
- The location of the active site has been revealed by the X-ray analysis of ATCase.
- Comparisons of structures with and without PALA have shown the large structural changes that ATCase undergoes.
- The active site of ATCase is an analog of PALA.
- At low concentrations, the distribution of ATCase molecule to the R is shifted.
- This increases the activity of the enzyme.
- BPG interacts with hemoglobin.
- The interaction between the negatively charged phosphates of BPG and the positively charged residues of hemoglobin is stronger in the interior environment than it would be on the surface.
- The force of interactions is proportional to the medium's dielectric constant.
- It is possible that the dielectric constant is as low as 2.
- The surface has a dielectric constant of 80, but the electrostatic interactions there are much more stable.
- Substance A wouldn't let oxygen into peripheral tissues.
- Oxygen wouldn't be loaded in the lungs with Substance B.
- An effective carrier has an oxygen dissociation curve between substance A and substance B.
- It would have a lot of oxygen in the lungs and less in the peripheral tissues.
- Administering enough oxygen to give saturation levels greater than 92 would be wasteful because one reaches the point of diminishing returns.
- The risk of compromising oxygen delivery to the tissues is caused by giving oxygen in amounts less than required.
- According to the model, a mixture of fully oxygenated and fully deoxygenated molecules is posed with all of the components in the R form.
- According to the sequential model, some of the molecule's parts are oxygenated in the R form and others are deoxygenated in the T form.
- There is a consensus that the Arg-Arg-X-Ser-Z is large and small.
- The site is either Ser or Thr.
- The activity of en zyme 1 should be decreased by phosphorylation.
- The steady-state ratio of [B]/[A] could be increased by an increase in cAMP levels.
- The control of opposing metabolic sequence is observed frequently in cells.
- The activation of trypsinogen is an autocatalytic process.
- trypsinogen can be cleaved as the process occurs.
- The activation of chymotrypsinogen corresponds to Curve II.
- The chymotrypsinogen is not autocatalytic.
- Tryspin can convert chymotrypsinogen to p-chymotrypsin.
- The time course is initially linear.
- The active site of trypsin needs to be partially buried.
- Thrombin cleaves bonds.
- When pro thrombin is converted to thrombin, there are two bonds that are broken.
- The conversion cannot be autocatalytic.
- Prepare two blood samples for testing.
- Factor XII deficiency is probably not involved if clotting time is restored to normal.
- Factor XII deficiency can be suspected if the addition of normal plasma restores normal time but the addition of Factor XII deficiency does not.
- The reaction is at equilibrium.
- Nothing would happen if the reaction was made more active.
- The reaction is still at equilibrium.
- If the reaction is displaced far from equilibrium, more product will be produced.
- If a regulatory enzyme is to increase the flux rate through a pathway, it must make an irreversible step.
- One molecule of active A will lead to the activation of more than one molecule of D. 103 molecule of active B will be produced by Active A.
- Each of the 103 molecule of active B will make 103 molecule of C. The total of active C and B is 106 and 103, respectively.
- Both thrombin and trypsin have an oxyanion hole at the active site.
- Both sites have a negatively charged pocket that can be binding.
- thrombin has enough space to accommodate a Gly residue next to the Arg binding site in contrast to trypsin, which has no restrictions as to the amino acid residue that can be accommodated at the corresponding position.
- The positive charge on the carbonyl oxygen in the transition state is thought to be stable by histidine 134.
- Whether one proceeds R - T -TS or R -RSTS, S is the same.
- The constant for the conversion of R to T and R toRS is 103.
- The constant for the conversion of T toTS is 10 since the affinity of R for S is 100 times that of T. The constant for the conversion ofRS toTS is 10.
- The R to T ratio is changed by the binding of the substrate with a hundredfold tighter binding to R.
- The ratio in the fully liganded molecule will be 10 if there is no substrate.
- L is the ratio of T to R in the sence of ligand, and L is the number 105.
- The fraction of the molecule in the R state is either [R]/([R] + [T]) or [R]/([R] + [R]Lj).
- The concerted model can't be counted for negative cooperativity due to the fact that the binding of substrate promotes a conformational transition of all subunits to the high-affinity R state.
- If the model holds, allosteric interactions must be cooperative.
- In the sequential model, the binding of ligand changes the structure of the subunit to which it is bound, but not that of its neighbors.
- The binding of PALA ATCase switches from the T to the R state.
- There are fewer free catalytic sites for an empty molecule than there are for a bound one.
- The R state of the PALA- containing enzyme makes it more affinity for the substrates.
- The binding affinities of the R and T states are for the analog.
- All of the time, the R state would be occupied by the Mutant enzyme.
- According to a classical saturation curve, the reaction rate depends on the fraction of active sites occupied by the substrate.
- A molecule with a high density of negative charge is needed to replace 2,3-BPG.
- The best candidate is (b) inositol hexaphosphate, an analogue of a major natural hemoglobin effector.
- The zymogens are activated by the cleavage of one or more bonds.
- The pepsin moities are hydrolyzed when the catalytic site is exposed.
- The time required for half the pepsinogen molecule to be activated is dependent on the number of molecules present.
- A mixture of the two bloods will not clot if both patients have a Factor VIII deficiency.
- If the second patient's bleeding disorder is caused by the deficiency of another factor, a mixture of the two bloods should clot.
- Factor X is used to convert prothrombin to thrombin on blood platelets.
- The proteolytic activation removes the fragment of prothrombin that contains Ca+2-binding sites and releases thrombin.
- Factor X can be activated by other prothrombin molecule if it remains bound to the platelets.
- It is thought that antithrombin III is not good for thrombin.
- Many en zyme inhibitors have high affinity for active sites.
- Thrombin can react with antithrombin III because it has a fully formed active site.
- Chapter 3 of your textbook introduces a coiled coil.
- Since this is a long molecule made up of repeating units, one would expect to see side chains at regular intervals.
- The binding of elastase by a1-antitrypsin is dependent on the side chain of methionine 358, which is most susceptible to oxidation by cigarette smoke.
- A side chain with a strong binding affinity for elastase is needed.
- The side chain of leucine is more stable than the side chain of methionine but has the same volume.
- The sequential model predicts that the fraction in the R state should be equal to the fraction in the Y.
- A conformational change in response to a distant site is reported by the change in the absorbance.
- The structure of a different trimer that carries the reporter nitrotyrosine group is altered by the binding of succinate to the active sites of a native trimer.
- Allosteric activators drive the catalytic subunits into the active state.
- The effect of CTP is to drive the catalytic subunits into an inactive state and decrease the absorbance.
- The effect is working here.
- The valine side chain on the surface tries to avoid water by making favorable van der Waals interactions with the leucine and phenylalanine side chains.
- The effect is to cause long fibers to crystallize and distort the shapes of red blood cells.
- In step 1, the aspartate smino group carries out a nucleophilic attack on the carbonyl carbon.
- The negatively charged oxyanion can be mitigated by the histidine in the active site.
- The serine- OH group takes the role of water and accepts the g-phosphate in the reaction.
- During the attack on the g-phosphate in step 1, the active site will need a group to accept the protons from the serine oxygen.
- The extra negative charge on the intermediate between steps 1 and 2 would be stable if there was a functional group at the active site.