Biochemistry
6th Edition
ISBN: 9781305577206
Author: Reginald H. Garrett, Charles M. Grisham
Publisher: Cengage Learning
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Chapter 19, Problem 4P
Understanding the Mechanism of the -Ketoglutarate Dehydrogenase Reaction tshe first step of the -Ketoglutarate dehydrogenase reaction involves decarboxylation of the substrate and leaves a covalent TPP intermediate. Write a reasonable mechanism for this reaction.
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Compare and contrast Pyruvate Dehydrogenase with a-ketoglutarate dehydrogenaseOutline the mechanisms of both enzymes. Discuss the functions of the coenzymes. List the similarities and the differences between the 2 enzymes. Both are very large membrane bound complexes. What are the advantages of this strategy?How detailed is the enzyme structure known below(It's Pyruvate Dehydrogenase )? What insight(s) does this structural detail give you about the enzyme mechanism.
H.
OH
co
co2
но
H co,
1-isopropylmalate
2-isopropylmalate
Biosynthesis of leucine involves conversion of 1-isopropyimalate to 2-isopropylmalate (see above). This proceeds in four steps under basic
enzymic catalysis via an isolable compound produced in step 2. Write a detailed mechanism for this conversion. Then, draw the intermediate
compound) produced in step 2.
• You do not have to consider stereochemistry.
• Draw uninvolved carboxyl groups in the anionic state, and enolates as carbanions.
When needed, abbreviate CoenzymeA-S- as CH3S- In your drawing.
aale
The glyceraldehyde-3-phosphate-deshydrogenase
glyceraldehyde-3-phosphate in 1,3-bisphosphoglycerate.
catalyses the
catalyses
-CH₂ -CHOH—CHO + Pi + NAD*
the oxidation of
CH₂ CHOH-COQ + H* + NADH
When the enzyme is incubated with iodoacetate, it is observed that glyceraldehyde-3-
phosphate still binds to the modified enzyme, but it is not oxidized. What conclusion
can be drawn from this experiment?
Data: iodoacetate ICH₂COO is an alkylating reagent that react with free sulfhydryl
groups (-SH) to form (-S-CH₂COO).
Chapter 19 Solutions
Biochemistry
Ch. 19 - Radiolabeling with 14C-Glutamate Describe the...Ch. 19 - Prob. 2PCh. 19 - Assessing the Effect of Active-Site...Ch. 19 - Understanding the Mechanism of the -Ketoglutarate...Ch. 19 - Understanding the Action of Fluoroacetate on the...Ch. 19 - Prob. 6PCh. 19 - Prob. 7PCh. 19 - Prob. 8PCh. 19 - Prob. 9PCh. 19 - Prob. 10P
Ch. 19 - Prob. 11PCh. 19 - Prob. 12PCh. 19 - Prob. 13PCh. 19 - Prob. 14PCh. 19 - Prob. 15PCh. 19 - Prob. 16PCh. 19 - Understanding the Oxidation of Glucose and Its...Ch. 19 - Prob. 18PCh. 19 - Prob. 19PCh. 19 - Prob. 20PCh. 19 - Complete oxidation of a 16-carbon fatty acid can...Ch. 19 - Study Figure 19.18 and decide which of the...Ch. 19 - Prob. 23P
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