Biochem Exam #4 - Biochemistry Exam#4 December 20,2007 Matt...

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Biochemistry Exam #4 December 20,2007 Matt McAllister and Brianna Watland Problem 1:
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Part A: Aspartate is glucogenic, this means that it can be converted into glucose. Aspartate transaminase converts aspartate into oxaloacetate. Then oxaloacetate is converted into phosphoenolpyruvate (PEP) by PEP
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carboxykinase. After PEP is synthesized, Enolase converts it into 2-Phosphoglycerate and that is converted into 3-Phosphoglycerate by Phosphoglycerate mutase. The 3- Phosphoglycerate is converted into 1,3-Bisphosphoglycerate by Phosphoglycerate kinase and this is converted into Glycraldehyde-3-phosphate by Glyceraldehydes-3-phosphate dehydrogenase. Glyceraldehyde-3-phosphate is converted to Fructose-1,6-bisphosphate by Fructose bisphosphate aldolase. Fructose-1,6-bisphosphate is converted into Fructose-6-bisphosphate by Fructose-1,6-bisphosphatase. Fructose-6-phosphate is converted into Glucose- 6-phosphate by Phosphoglucoisomerase. Glucose-6-phosphate is converted into Glucose by Glucose-6-phosphatase. Part B: Threonine is converted into Glycine and Acetaldehyde by cleaving the C2 and C3 bond. Glycine is then converted into Serine by N 5 ,N 10 -Methylene THF. Serine is then deaminated by serine dehydrase to yield pyruvate.
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Problem 2: Both glutamate and aspartate function as excitatory neurotransmitters through the central nervous system. Glutamate not only is responsible for the flavor of food, it also is a special part in amino acid breakdown. Glutamate is chemically related to 2-oxoglutarate, which is a key intermediate in the TCA cycle. Because of this glutamate can be reversibly changed into 2-oxoglutarate by glutamate dehydrogenase, or can be reversibly changed into glutamine. Glutamate is formed from a-ketoglutarate, which is a citric acid cycle intermediate.
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Aspartate is formed from oxaloacetate, which is a citric acid cycle intermediate. Asparate also is be transaminated to asparagines through a ATP-dependent reaction that is catalyzed by asparagines synthetase and glutamine is the amino group donor. “The synthesis of glutamine is a two-step one in which glutamate is first "activated" to a g-glutamylphosphate intermediate, followed by a reaction in which NH 3 displaces the phosphate group. So, the synthesis of asparagine is intrinsically tied to that of glutamine, and it turns out that glutamine is the amino group donor in the formation of numerous biosynthetic products, as well as being a storage form of NH 3 . Therefore, one would expect that glutamine synthetase, the enzyme responsible for the amidation of glutamate, plays a central role in the regulation of nitrogen metabolism.”
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Problem 3: Enzyme Cellular Location Reactant(s) Product(s) Key Feature of
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This test prep was uploaded on 04/17/2008 for the course HIST 002 taught by Professor Mcfarland during the Spring '07 term at Drake University .

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Biochem Exam #4 - Biochemistry Exam#4 December 20,2007 Matt...

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