Humans Bacteria 4. (0.75 pts) Phosphoenolpyruvate carboxykinase (PEPCK) is an im

Question

Humans Bacteria 4. (0.75 pts) Phosphoenolpyruvate carboxykinase (PEPCK) is an important enzyme in energy metabolism that catalyzes the conversion of oxaloacetate (OAA) to phosphoenolpyruvate (PEP) using GTP (in animals and humans) and has no known allosteric kinetic properties or physiological modulators. However, the level of PEPCK activity regulates gluconeogenesis. The i formation of (PEP) by directly phosphorylating pyruvate is not possible in animals or humans but does occur in Ony AM rect CO bacteria by the enzyme phosphoenolpyruvate synthea (a) (0.1 pts) In humans (and animals), another enzyme is needed to convert pyruvate to oxaloacetate. What is the name of this enzyme and write out its chemical reaction (not mechanism). (b) (0.1 pts) In comparison of the two different pathways to generate phosphoenolpyruvate from pyruvate which one is more chemically efficient and why? (c) (0.4 pts) Based on the thermodynamics of hydrolysis of nucleotides listed in Table 10.2 (refer to your textbook or lecture notes) calculate the amount of available free energy (as 0") that can be used to covert pyruvate to phosphoenolpyruvate. Assume the values in Table 10.2 apply to the guanylyl analogs as well. (d) (0.15 pts) What metabolic advantage, if any, would the two enzyme system in humans have compared to the one enzyme system in bacteria?

Explanation / Answer

a) Pyruvate Carboxylase to convert pyruvate to oxalacetate the reaction was pyruvate to oxalacetate by consuming ATP to ADP + pi using Pyruvate carboxylase enzyme to get oxalacetate

b. chemmically it is mor efficient in bacteria because it is a single step process and easily convertable

c. for bacteria the energy will be -4.7kj/Mol-1

and for animals it will be -32/-31.8 kj/Mol-1

b. bacterial pathway is more coveniant than human because it is a single step and also free energy will be more

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