Interpretation:
The list of all the modulators of oxygen binding by hemoglobin discussed in the given chapter is to be stated. The way by which the given modulators enhance the function of hemoglobin under physiological conditions is to be stated. Whether any of the modulator of hemoglobin also functions similarly in myoglobin or not is to be stated. The reason corresponding to the correct choice is to be stated.
Concept introduction:
Proteins are the
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- Suppose you mutate the proximal histidine of hemoglobin to glycine. You study the behavior of this mutant hemoglobin in the presence of 10 mM imidazole; the imidazole molecule can substitute for the proximal histidine chain and bind to the heme iron just as histidine does. a) Which state (T or R) will this mutation favor? b) Will oxygen binding to this state be tighter or weaker than oxygen binding to the same state of the wildtype hemoglobin? (note: wildtype means refers to the phenotype of the typical form of a species as it occurs in nature) c) Will this mutant still display significant cooperativity?arrow_forwardFrom the figure of O2 binding to myoglobin and hemoglobin (ignore the linemarked as T) as described in lecture (shown below) answer the following questions. a) Estimate the P50 for myoglobin from the plot. Show how this estimation isdetermined from the binding curve above. ( The first ghraph) b)Using YO2 = PO2/P50 + PO2 , calculate the fraction of O2 bound for myoglobin at 1 torr. (2nd graph) c)Using the binding curve on the previous page, show how you can estimate whatfraction of hemoglobin is bound near tissues at a pO2 of 30 torr and provide this value. If the pH were lowered, will the amount of O2 bound to hemoglobin at 30 torr increaseor decrease? Explain why this is so based on how this changes hemoglobin structure. If 2,3-BPG were added to the solution, will the amount of O2 bound to hemoglobin at30 torr increase or decrease? Explain why this is so based on how this changes hemoglobinstructure.arrow_forwardBPC is a heterotropic allosteric modulator. in which way does this compound change the uptake and release of oxygen in hemoglobin?arrow_forward
- Studies of oxygen transport in pregnant mammals have shown that the O2-saturation curves of fetal and maternal blood are markedly different when measured under the same conditions. Fetal erythrocytes contain a structural variant of hemoglobin, HbF, consisting of two γ and two β subunits (γ2β2), whereas maternal erythrocytes contain HbA (α2β2). (a) Which hemoglobin has a higher affinity for oxygen under physiological conditions, HbA or HbF? Explain. (b) What is the physiological significance of the different O2 affinities? (c) When all the BPG is carefully removed from samples of HbA and HbF, the measured O2-saturation curves (and consequently the O2 affinities) are displaced to the left. However, HbA now has a greater affinity for oxygen than does HbF. When BPG is reintroduced, the O2-saturation curves return to normal, as shown in the graph. What is the effect of BPG on the O2 affinity of hemoglobin? How can the above information be used to explain the different O2 affinities of…arrow_forwardCalculate the percent oxygen saturation of myoglobin if 7 of 15 binding sites are occupied..arrow_forward2,3 BPG is an allosteric effector that decrease haemoglobin affinity for oxygen by stabilizing the T-state of deoxyhaemoglobin. This lead to the release of oxygen to cells and body tissues for use. H atom and CO2 are also allosteric effector and can do same. How?arrow_forward
- To study the chemical properties of the blood hemoglobin of a vertebrate, it might seem convenient to remove the hemoglobin from the red blood cells so that the hemoglobin is in simple aqueous solution. However, removing the hemoglobin from red blood cells often promptly alters its O2-binding characteristics. Why?arrow_forwardHemoglobin from different species can have different numbers of subunits. Let's consider three hemoglobin molecules: n = 1, n = 4, and n = 8, where each subunit has an oxygen P50 = 30 torr. (Recall that Pso is essentially a Kp and that oxygen partial pressure (torr) is directly proportional to concentration.) Which molecule transports the most O2 between the lungs (pO2 = 100 torr) and peripheral tissues (pO2 = 30 torr)? Please justify your answer.arrow_forwardTo study the chemical properties of the blood hemoglobin of a vertebrate, it might seem convenient to remove the hemoglobin from the red blood cells so that hemoglobin is in simple aqueous solution. However, removing the hemoglobin from red blood cells often promptly alters its O2-binding characteristics. Explain why?arrow_forward
- You have discovered a new form of mouse myoglobin that has a p50 of 9 Torr. At approximately what pO2 would this hemoglobin be 86% saturated with oxygen? 85 Torr 40 Torr 60 Torr 55 Torr Not enough information is given to answer this questionarrow_forwardAmino acid substitutions at the interfaces of the a and B subunits of hemoglobin can change the relative stability of the oxy (R) and deoxy (T) forms of the molecule. In one mutant hemoglobin molecule a hydrogen bond involved in stabilizing the R form of the molecule is lost. As a result, would expect this mutant hemoglobin to have a higher or lower affinity for oxygen as a ligand. Explain.arrow_forwardI now know the structure difference between myoglobin and hemoglobin , however which exctaly structure difference make myglobin become a oxygen storage ? and not a oxygen transport?? Be specific! details describe how the structure connect to their role. also which exctaly structure difference make hemoglobin become better oxygen transport?? I need the specific structure that contribute to their unique role. I KNOW THE STRUCTURE DIFFERENCE , but don't understand which specific part make myoglobin only bind to oxygen, and not release oxygenarrow_forward
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