17.S: The Oganic Chemistry of Vitamins (Summary)
- Page ID
- 106697
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After completing this chapter, you should be able to:
- Understand how pyridoxal phosphate (PLP) acts as an 'electron sink' in a variety of reactions in amino acid metabolism.
- Recognize and draw mechanisms for PLP-dependent transformations of the following types:
- racemization
- decarboxylation
- transamination
- retroaldol cleavage
- retro-Claisen cleavage
- \(\beta \)-elimination
- \(\beta \)-substitution
- \(\gamma \)-elimination
- \(\gamma \)-substitution
- Recognize transformations - amino acid decarboxylation and transamination, for example - in which chemical steps occur that simply don't 'make sense' unless the electron sink role of PLP is taken into account.
- Understand how the orientation of the substrate in relation to the plane formed by the conjugated \(\pi \) system of PLP is a major factor in catalysis of PLP-dependent reactions.
- Understand how thiamine diphosphate (\(ThDP\)) acts as an 'electron sink' in a variety of reactions in which a bond to a carbonyl carbon is broken, and how these steps do not 'make sense' unless the electron sink role of \(ThDP\) is taken into account.
- Recognize transformations for which \(ThDP\) is likely required, and be able to draw reasonable mechanisms for them.
- Understand how \(ThDP\) acts in tandem with lipoamide, flavin, and nicotinamide in the reaction catalyzed by pyruvate dehydrogenase.
- Recognize folate in its various forms - \(DHF\), \(THF\), \(f-THF\), \(CH_2-THF\), and \(CH_3-THF\) - functions in a variety of one-carbon transfer steps. Be able to recognize the oxidation state of the carbon being transferred in a folate-depenent step.