Term
| What are the two main classes of amino acids and how are they divided? |
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Definition
1. Essential and Non Essential
2. Essential must come from diet or protein degradation, non essential can be synthesized in mammals |
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Term
| What is the cofactor involved in aminotransferases, where does it come from, and what purpose does it serve? |
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Definition
1. Pyridoxal phosphate
2. Derivative of vitamin B6
3. Shuttle point for amino group in transferring process |
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Term
| What enzyme converts phenylalanine to tyrosine? What is the essential cofactor? |
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Definition
1. Phenylalaine hydoxylase
2. BH4
Note: BH4 goes to BH2 and is reconverted by NADH to BH4
Elevated Phe caused by problems in this pathway lead to altered brain function |
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Term
| What are some of the roles of tyrosine? |
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Definition
1. Make melanin
2. Synthesize catecholamines (again, uses BH4)
3. Degrade to fumarate and aceto acetate |
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Term
| What is the disorder called when Phenylalanine cannot be converted to Tyrosine? |
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Definition
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Term
| What is the universal first step in amino acid degradation? |
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Definition
| Removal of alpha amino group |
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Term
| What are the two classes in terms of whether degraded amino acids can be used for gluconeogenesis or not? What determines what type they are? |
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Definition
1. Glucogenic or ketogenic
2. Where their carbon skeleton breakdown product falls in the TCA cycle. If its acetoacetate or acetyl CoA, carbons will be burned off in the TCA cycle and it is ketogenic. Any other intermediate (pyruvate, alpha ketoglutarate, oxaloacetate, fumarate, succinyl CoA) are glucogenic |
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Term
| What are the 3 branched chain amino acids? |
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Definition
Leucine, isoleucine, and valine
Note: all are essential AA |
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Term
| How do branched chain amino acids enter the mitochondrion? What types of activity happens here? |
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Definition
BCATm - branched chain amino acid aminotransferase
Converts AA to alpha keto acids upon pumping them into the mitochondria |
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Term
| What enzyme breaks down the branched chain alpha keto acids into TCA cycle components? |
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Definition
| Branched Chain alpha keto acid dehydrogenase |
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Term
| What are the 3 potential end products of the breakdown of branched chain amino acids? |
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Definition
Succinyl CoA (glucogenic)
Aceytl CoA (ketogenic)
Acetoacetyl CoA (ketogenic) |
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Term
| What is maple syrup urine disease? |
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Definition
A deficiency in the branched chain alpha keto acid dehydrogenase enzyme (BKCD)
Leads to a buildup of leucine, isoleucine, valine, and their alpha keto acids in the blood
Gives urine characteristic odor and leads to mental retardation |
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Term
| Where does THF (Tetrahydrofolate) come from and what is its function? |
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Definition
1. Breakdown of Glycine by Glycine Cleave complex, as well as conversion of folic acid by dihydropholate reductase (needs NADPH)
2. THF is a critical molecule capable of donating individual carbons in reactions
Note: Absence of Glycine Cleavage Complex leads to nonketotic hyperglycinemia |
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Term
| What is SAM, what is it synthesized from, and what is its role? |
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Definition
1. S-adenosylmethione
2. Synthesized from methionine (via SAM synthetase)
3. It is the MAJOR methy group donor in one carbon metabolism |
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Term
| What is the end product of SAM reactions and what is its importance? |
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Definition
SAM produces SAH
SAH is toxic and needs to be reconverted to Cysteine or Methionine |
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Term
| What is serotonin synthesized from? What is the cofactor? |
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Definition
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Term
| What are catecholamines synthesized from? What are the cofactors? What is the rate limiting step? |
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Definition
1. Synthesized from Tyrosine
2. BH4, B6, Vit C, and SAM are the cofactors
3. Rate limiting step is dehydroxylation of Tyrosine with BH4 as a cofactor |
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Term
| What amino acids are involved in the synthesis of creating? What is the committed step? |
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Definition
1. Arginine, Methioning, Glycine
2. Breakdown of Glycine to ornithine and guanidinoacetate is the committed step |
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Term
| What amino acids are involved in the synthesis of creating? What is the committed step? |
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Definition
1. Arginine, Methioning, Glycine
2. Breakdown of Glycine to ornithine and guanidinoacetate is the committed step |
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