Lecture 35 Flashcards
(22 cards)
What are important non-protein derivatives of amino acids?
coenzymes, hormones, other nitrogenous compounds, phospholipids, neurotransmitters, carbohydrate intermediates, glycogen and glucose, purines and pyrimidines (chop, north carolina, Gore for President)
What is drawn off of the glycolytic pathway to produce serine? What type of reaction is involved in serine synthesis and what type of molecules are utilized in said reaction?
- 3-phosphoglycerate
- aminotransferase, glutamate gets converted to alpha-ketoglutarate
Is there an aminotransferase reaction involved in the metabolism of serine? What substrate is used? Is the synthesis/degradation of serine a reverse pathway? What is it’s connection to CHO metabolism?
- yes
- alpha-ketoacid gets converted to alpha-amino acid
- no
- use of 3-phosphoglycerate
What substrate is utilized as a substrate in the conversion of serine to glycine? What is this cofactor derived from? What does it give off? What is accepted by said substrate? Can the reverse reaction occur? What goes into it?
- H4folate, tetrahydrafolate, folic acid
- b-vitamin derived co-factor
- H2O
- 1 carbon unit off of serine
- yes
- H2O
What cofactor is used in the destruction of glycine? What is created in this reaction? What does the H4folate become?
- H4folate
- NADH, CO2, NH3
- methylene H4folate
Which vitamin is folic acid? What are the attachment points for transferrable carbons? What is Folic acid called when no glutamate is attached?
- Vitamin B9
- N5 and N10
- Pteroic acid
Does Folic acid perform 1C group transfers? N5 is the site of attachment for what? N10?
- yes
- methyl and formimino
- formyl
What are the different states of the folic acid and what do they do? What is responsible for these different states?
- methyl (homocysteine>methionine), methylene (glycine>serine), methenyl (histidine>formiminoglutamate), formyl (tear apart tryptophan)
- different oxidation/reduction states of the carbon
What enzyme converts phenylalanine to tyrosine? What is caused by a defect in this enzyme? How is this problem addressed?
- Phenylalanine hydroxylase
- Phenylketonuria (neurological damage)
- limit dietary phenylalanine
What reaction occurs in breakdown of tyrosine? What happens to ring? What metabolites are produced and what can be done with them?
- aminotransferases (lose the amino group)
- breaks
- fumarate, acetoacetate (common CHO metabolites can be used to make acetyl CoA or make glucose)
What catecholamines can be synthesized from Tyrosine?
- Dopamine > norepinephrine > epinephrine
What serves as the source of a 1 carbon unit transfer when making epinephrine from norepinephrine?
S-adenosylmethionine (SAM)
What is used to make S-adenosylmethionine?
methionine and ATP (enzyme methionine adenosyltransferase)
What two compounds result from the loss of CH3 (what does this make) from S-adenosylmethionine and then adenosine? Which of these two will receive the SH (sulfur)?
- (S-adenosylhomocysteine) Homocysteine and Serine
- Serine
What is made from homocysteine and serine? What is the enzyme? What does this compound get split into and by which enzyme?
- Cystathione
- cystathione synthase
- alpha-ketobutyrate and cysteine (the second sulfur containing AA) by cystathionase
Is cysteine an essential AA?
- on the edge - can be made from methionine - but only if there is enough methionine available
What cofactor is used is the conversion of homocysteine to methionine? Can THF and SAM combine in 1C transfer?
- methyl-H4folate
- yes
What compound is taurine synthesized from? What species doesn’t do this well? What two things does this illustrate?
- Cysteine
- Kit-beans
- we have other alternative pathways that convert amino acids into other molecules required in normal metabolism - sometimes particular species don’t do well without dietary supplements
What are some things Taurine does?
- Brain development
- Muscle and retina
- Conjugation
- Antioxidant
- Membrane Stabilizer
- Osmoregulation
What are some useful things that can be gained from breakdown of tryptophan? Is it all useful?
- Nicotinate mononucleate (half of NAD), start of Acetoacetyl CoA, vitamin B6
- no, a bunch of it is excreted
What is common between Valine, Isoleucine, and Leucine breakdown? What does this illustrate?
- use of amino-transferase and alpha-keto acid dehydrogenase
- these three share enough structural properties (branched-chain) that they can also share some of the same degradation pathways
What causes a patient’s urine to smell like maple syrup?
- a deficiency in branched chain keto acid dehyrdogenase that causes patients to excrete branched chain keto acids that smell like maple syrup!! whoa dude (others - sweaty feet and cat urine…)
