NAD+ -dependent Glyceraldehyde-3-phosphate + Dehydrogenase from Thermoproteus tenax. 1. Name the three enzymes that catalyze irreversible,...

NAD+ -dependent Glyceraldehyde-3-phosphate + Dehydrogenase from Thermoproteus tenax.

1. Name the three enzymes that catalyze irreversible, regulated reactions in glycolysis as studied in class.

2. What is the significance of the GAPDH reaction in E. coli to glycolysis?

3. How does the reaction catalyzed by GAPDH from T. tenax presented here differ from the reaction carried out in E. coli?

4. The activity of the GAPDH enzyme was assayed in the presence of a constant amount of glyceraldehyde-3-phosphate and an increasing amount of NAD . The activity of the control was + compared to the activity in the presence of various metabolites. The results are shown in Figure 20.2. Additional data are given in Table 20.2.

a. Use the data in Figure 20.2 to estimate a KM value for the enzyme in the presence of these metabolites. Classify the metabolites listed in Table 20.2 as inhibitors or activators. Fill in your answers in the table provided. Explain how you decided whether these metabolites are inhibitors or activators, based on the graph.

b. How would you classify NADH, ADP and ATP? (These data are not presented in the graph). Are they inhibitors or activators? Add this information to Table 20.2.

c. Explain the physiological significance of your answers to questions 4a and 4b. NAD+ -dependent Glyceraldehyde-3-phosphate + Dehyd

5. In the absence of NADP+, the binding of NAD+ to the T. tenax GAPDH showed no cooperative binding (closed circles, Figure 2 above). In the presence of NADP however, the binding of NAD+ to the T. tenax GAPDH was found to have a Hill coefficient of 2 (open circles, Figure 2 above).

a) What is the significance of the change in the value of the Hill coefficient?

b) Is this consistent with the shape of the curve and the information given in the background concerning the enzyme's quaternary structure?

6. What is the ATP yield for one mole of glucose oxidized by the pathway that uses the non-phosphorylating GAPDH enzyme?

Expert Solution

gladiator answered 1 year ago

1. What is the effect that glyceraldehyde 3 phosphate dehydrogenase has on cells? 2. What would...

1. What is the effect that glyceraldehyde 3 phosphate dehydrogenase has on cells? 2. What would happen in the absence of Pol1, if the the primers are not replaced by DNA and if Pol 3 was absent and no DNA synthesis occured? 3. How does the phase where Glucose forms glucose 6 phosphate differ from the phase where PGA forms pyruvate in terms of reaction coupling to overcome thermodynamic hurdles for glycolysis to occur ***

Fred had conducted a PCR experiment for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene. This is a house-keeping gene....

Fred had conducted a PCR experiment for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene. This is a house-keeping gene. He was searching the following primers from the following sequence: 1 ccgtattcag cattctatgc tctcaagtta tgaaacagga aatgatgacc tcctgaactt 61 gaggcagttt aactactact ttttttaaaa aggcaccaag atacttacaa aaacattttt 121 cttgttttgt ttctccatgg tttgagttta cttttaaaac tttcttttca ccagctattt 181 tggagattaa tctaacaaaa aacatgaaac ttaaatatat tttggaaatc taaattatac 241 ttagagactt aaatacattt tgctgatgac tggttacaat acagttacag actaggtata 301 tgttaaattt gaataaaaag ttattaaagc attaatcttt ttcctttcgc aaaacaagtt 361 caccaccatg tgaaataatt tcaaattaat gcataagatg tttcttccat ttacaaccac 421 aacgattctt ctgtaagtca agctcctacc attcatgctg...

Both glyceraldehyde 3-phosphate and dihydroxyacetone phosphate are substrates for the enzyme triose phosphate isomerase. In a...

Both glyceraldehyde 3-phosphate and dihydroxyacetone phosphate are substrates for the enzyme triose phosphate isomerase. In a study by Knowles et al the kM for glyceraldehyde 3-phosphate was determined to be 0.47mM with a Vmax of about 410 uM/min. Whereas, for the substrate dihydroxyacetone phosphate the kM was determined to be 0.97 mM and the Vmax was about 41 uM/min. (Biochem J 129 (2) 1972:301-310). Triose phosphate isomerase has a relatively weak affinity for _______ A. glyceraldehyde 3-phosphate because the kM...

Which pathway reduces the most NAD+? 1. Glycolysis 2. Pyruvate Dehydrogenase Complex 3. Both Pyruvate Dehydrogenase...

Which pathway reduces the most NAD+? 1. Glycolysis 2. Pyruvate Dehydrogenase Complex 3. Both Pyruvate Dehydrogenase Complex & Glycolysis are the same as each other but greater than fermentation 4. Fermentation

In order to produce three glyceraldehyde-3-phosphate molecules that the plant could use to make other organic...

In order to produce three glyceraldehyde-3-phosphate molecules that the plant could use to make other organic molecules, how many CO2 molecules would have to enter the Calvin Cycle? 3 6 9 12 Genes A and B are on the same chromosome. If a person has one chromosome with the alleles AB and a second chromosome with the alleles ab, how could they produce a gamete with a chromosome containing the alleles Ab or aB? independent assortment random fertilization crossing over...

1) write the balanced net reaction of the conversion of glyceraldehyde 3-phosphate into lactate 2)If all...

1) write the balanced net reaction of the conversion of glyceraldehyde 3-phosphate into lactate 2)If all the glucose were metabolized through that 2,3-BPG shunt into lactate, what should be the net reaction for the conversion of glucose to lactate?

Fructose-1,6-bisphosphate (FBP) <=====> glyceraldehyde-3-phosphate (GAP) + dihydroxyacetone phosphate (DHAP) The standard free energy change for this...

Fructose-1,6-bisphosphate (FBP) <=====> glyceraldehyde-3-phosphate (GAP) + dihydroxyacetone phosphate (DHAP) The standard free energy change for this reaction is +22.8 kJ/mol. Under actual conditions in the cell the concentrations of GAP,DHAP,and FBP are 0.5 mM, 0.3 mM, and 6.0 mM respectively. Given this information calculate the actual free energy change for this reaction in the cell at a temperature of 37 oC. Provide your answer (just the numerical part) in kJ/mole to two signicant figures

A)Triosephosphate isomerase(TIM)converts dihydroxyacetone phosphate (DHAP) into glyceraldehyde-3-phosphate (GAP) and vice-versa. This is one of the best-understood...

A)Triosephosphate isomerase(TIM)converts dihydroxyacetone phosphate (DHAP) into glyceraldehyde-3-phosphate (GAP) and vice-versa. This is one of the best-understood enzyme reactions. It has been studied extensively and we know the two critical side chains in the active site of TIM that catalyze the isomerization reaction. Write the mechanism of TIM showing the two catalytic side chains. B) In the TIM reaction, the histidine residue starts off neutral, not positively charged (as one might expect since it donates a proton to the O-group). Explain...

QUESTION 39 The molecule that traps the sun's energy is   ATP.  chloroplast.  chlorophyll.  glyceraldehyde-3-phosphate &nbsp

QUESTION 39 The molecule that traps the sun's energy is   ATP.  chloroplast.  chlorophyll.  glyceraldehyde-3-phosphate QUESTION 42 Deleterious mutations increase the fitness of the organism. True False QUESTION 47 The light-independent reactions of photosynthesis (Calvin cycle) take place in the   cytoplasm.  grana.  thylakoids.  stroma. QUESTION 48 Cellular respiration is endergonic. True False QUESTION 49 The ATP and NADPH produced in the light-dependent reaction stage   are the end products of photosynthesis.  become reactants for cellular respiration.  are waste products that the...

Which of the following enzymes is very important in determining the partitioning of glyceraldehyle-3-phosphate/dihydroxy acetone phosphate...

Which of the following enzymes is very important in determining the partitioning of glyceraldehyle-3-phosphate/dihydroxy acetone phosphate between starch synthesis and sucrose synthesis Aquaporins G3P/DHAP efflux channel RubisCO Triose-phosphate translocator ATPases The accumulation of phosphorylated sugars in the cytoplasm will Increase the activity of certain key Calvin Cycle enzymes Promote export of phosphorylated sugars in the phloem Promote export of triose-P from the chloroplast Promote starch synthesis in the chloroplast Promote starch degradation in the chloroplast A tomato fruit growing on...

Question