Fat Metabolism, cont.
Fatty Acid Biosynthesis
- What are chemical reactions?
- What is reducing agent?
- Why? (2 reasons)
- What are sources of reducing equivalents?
- How is AcCoA "activated?"
- Compare the enzyme involved to Pyruvate Carboxylase.
- How is AcCoA carboxylase regulated?
- beta-oxidation is a thermo favorable process; so is fatty acid biosynthesis. How is this apparent paradox resolved?
- Rationalize the use of citrate and palmitoyl CoA as regulatory substances.
- What are the activities of the FattyAcid synthase complex?
- What is ACP1?
- How do they differ in function?
- In regards to binding?
- What is the Pyruvate Malate Shuttle?
- Be able to outline this series of reactions.
- Integrate FA biosynthesis with the production of reducing equivalents assuming glucose as the ultimate precursor.
- Don't forget compartmentation.
- How is the control of b-oxidation, ketogenesis and F.A. synthesis coordinated?
Draw a path, as we did in class, tracing the production of a fatty acid molecule from glucose.
- Which of the pathways and/or cycles we have seen in class contribute to this process?
- Starting with serum glucose:
- Show how all of the carbons can be supplied by glucose.
- Show how all of the reducing equivalents can be ultimately derived from glucose.
- Can all of the ATP energy required by this process be supplied by your scheme using just cytosolic reactions?
- Can the energy required for fat synthesis from AcCoA be supplied by your scheme using just mitosolic sources without using Kreb's Cycle/ETS ATP production?
- Calculate the minimum number of glucose molecules needed to synthesize palmitate using your scheme.
Consider the biosynthesis of a molecule of 2-palmitoyl-1,3-distearoylglycerol molecule:
- How many glucose molecules would be required to provide the carbons in this fat molecule?
Discuss the regulation of fatty acid metabolism within a single cell:
- Consider that the cell is ATP rich, that is the energy charge (EC) is very high.
- How will this affect the ETS?
- If glycolysis still functions at a reduced rate, what will happen to the carbon?
- What will the various effectors of PFK be?
- How will Pentose -P be regulated?
Metabolism of Amino Acid Nitrogen
- Rationalize the different forms of excreted nitrogen.
- What is the major reaction for NH3 production?
- Know Glutamate D.H.:
- reaction catalyzed, function
- What are the major transaminases?
- What are their functions?
- What is the reaction catalyzed?
- Explain why this is a redox reaction.
- Know the mechanism of action of this family of enzymes:
- details of pyridoxal-P involvement (including structures)
- formation of Shiff base; "electron sink;"
- electrophilic attack
- bond labilized.
- What other bonds in amino acids may be labilized by Pyridoxal-P?
- Write a kinetic mechanism diagram for transaminase.
- How are serine and threonine deaminated?
- How are GluNH3 and AspNH3 deaminated?
- How are D-amino acids deaminated?
©R A Paselk
Last modified 19 April 2011