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189 Cards in this Set
- Front
- Back
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What are the three functions of protein turnover?
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1) N storage
2) Remove abnormal proteins 3) regulation-short 1/2 lives |
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What are the two types of degradation?
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Lysosomal and Ubiquitination
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Lysosomal degredation has a pH optimum of ___. Is it selective or nonselective in well nourished cells? Starvation?
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5; nonselective; selective
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What code does lysosomal degredation recognize on proteins?
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KFERQ
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When lysosomal degradation is selective, it searches for proteins with what sequence? Where are they found?
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KFERQ; liver and kidney (NOT in brain!)
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Draw out an isopeptide linkage.
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.
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What does the isopeptide bond show?
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It marks the protein for degradation (Ubiquitination)
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Ubiquitin contains how many AA's?
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76; highly conserved (same in many species)
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What sequence does ubiquitin look for on proteins?
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PEST
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Is ubiquitination regulated?
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Highly!
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The N-End rule applies to what type of degradation?
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Ubiquitination. 2-3 min 1/2 life or > 10 hours
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Pyruvate is a product of
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AA degradation and glycolysis
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Acetyl CoA gives rise to _____ but not _____.
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ketone bodies; glucose
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FA are broken down by __ to form _____.
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beta oxid.; Acetyl CoA (which turns into Malonyl CoA..the substrate for FA synth.)
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In AA metabolism, the amino group is disposed of via
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Urea Synthesis
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If a protein contains the sequence PEST, it is
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rapidly degraded by ubiquitin
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What destroys ubiquitinated proteins?
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Proteosome
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What removes ubiquitin from a protein?
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Ubiquitin isopeptidase. (Doomed proteins have at least 4 ubiquitins on them)
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What is the proteosome composed of?
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20S region with two 19S caps
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What do the 19S caps do? 20S region?
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Select and unfold ubiquinated proteins; breaks protein into ~8 AA fragments + ubiq (requires ATP)
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Transamination is used in __; What happens?
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AA metabolism; amino group of AA and =O of mol. switch places
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What is the first TA reaction with an AA?
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AA + alpha KG --> alpha keto acid + glutamate (requires PLP)
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Transamination rxns use what enzyme? What do these enzymes require?
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Aminotransferases or transaminases; PLP (pyridoxyl-5'-phosphate)
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Recognize Vit B6
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.
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Vit. B6 --> PLP via what type of reaction?
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Dehydration
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Draw PLP
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.
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Draw PLP Schiff Base
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.
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AA carbon skeletons go on to make what four things?
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CO2 + H20, Glucose, Acetyl CoA, Ketone bodies
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The three steps of the TA mechanism
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1) Transimination
2) Tautomerization 3) Hydrolysis |
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The third step of the TA mechanism ends with what products?
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PMP and alpha keto acid
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Glutamate is made into NH4+ and alpha KG with what enzyme? Where does NH4+ do?
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Glutamate DH; Urea cycle..apha KG goes on to help with more TA rxns
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What is the point of having Glutamate DH?
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To get rid of excess ammonia on AA's!
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How do people excrete ammonia? Fish? Birds and reptiles?
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Urea; ammonia; uric acid crystals
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If you have too much NH4+ to get rid of what happens to you?
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You are lethargic and retarded
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You use a lot of ____ to get rid of N.
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water
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Where does the Urea Cycle take place?
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cytosol and mitochondria
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Glutamate DH requires what cofactor?
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NAD(P)+
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The =0 on urea is from what molecule? C?
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water; bicarbonate
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In the urea cycle, AA #1 goes through __ TA rxns and AA#2 goes through __ TA rxns.
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1 (Its second rxn is glu DH); 2
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AA#2 goes through BOTH TA steps in the book. T/F
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True; yields Asp
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NH4+ from AA#1 is added to bicarb and 2 ATP to make
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Carbamoyl phosphate + 2 ADP + Pi (The 1st ATP is taken off, the 2nd stays on)
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What is the rate limiting step in the urea cycle?
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1 (carbamoyl synth. #1)
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H20 + CO2 -->
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Bicarbonate
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Carbamoyl P synth #1 is used in ___, and CPS2 is used in ___.
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urea cycle; nucleic acid metabolism
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The first rxn in Urea cycle makes __. 2nd? 3rd? 4th? 5th?
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Carbamoyl P; Citrulline; Arginino-succinate; Fumarate and Arginine; Urea and Ornithine
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In the Urea Cycle, ATP is required for which steps?
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1 and 3
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Aspartate is needed for which step of the Urea Cycle?
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3 (with citrulline and 1 ATP)
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Fumarate is made in which step of the Urea cycle?
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4 (It goes on to make malate --> OXAL which is used with AA#2 for step 3 with Asp)
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Urea is made in which step of the Urea Cycle?
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5 (with the addition of H2O)`
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Arginine + H2O -->
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Urea
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Citrulline + ATP + Aspartate -->
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Arginino-succinate
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In step 3 of the Urea Cycle the amino group of aspartate attacks the c=o of citrulline to make
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fumarate (from Asp) and Arginine (from citrulline)
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How can you make NADPH?
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Urea cycle and G6P DH
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Carbamoyl P + OXAL -->
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Citrulline
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What is the enzyme used in rxn 2 of UC?
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Ornithine transcarbamoylase
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What is the enzyme used in rxn 1 of UC?
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CPS I
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What is the enzyme used in rxn 3 of UC?
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Argininosuccinate synthase
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What is the enzyme used in rxn 4 of UC?
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Argininosuccinase
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What is the enzyme used in rxn 5 of UC?
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Arginase
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What activates CPS I? How is it made?
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N-Acetyl-Glu (NAG); Acetyl CoA + Glu
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T/F: Inc AA --> Inc NAG --> Ing CPSI activity --> Inc Urea
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True
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Hyperamonemia is caused from what?
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Mutations that reduce Urea Cycle efficiency (lethargy and retardation) Treat with NAG analogs and increased Arg
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Amino acids can go on to do what two things?
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be Gluconeogenic (make glucose) or Ketogenic (make acetyl CoA) or BOTH
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Which AA make Pyruvate?
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Alanine, Glycine, Serine, Threonine..TA!!
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Which amino acids make alpha-KG?
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Arginine, Glutamate, Glutamine, Proline...TA!!
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Which amino acids make OXAL?
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Asparagine and Aspartate..Glu DH!! (Needs NAD(P)+)
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If you do not have enough Phe hydroxylase, you will get
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Phenylketonuria (PKU)
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If you have PKU you should not eat
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Phe products! Such as Nutrasweet!
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Threonine -->
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Glycine (Serine Hydroxymethyl transferase)
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2 Glycine -->
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Serine (THF + Serine Hydroxymethyl Transferase)
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Alanine-->
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Pyruvate (TA..alpha KG needed)
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Serine -->
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Pyruvate (Serine dehydratase..releases NH3)
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To make PLP Schiff base resonance stabilized,
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remove H, R, or COO
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Thre-->Gly requires PLP. Then PLPSB removes ___ to make it stable
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R group
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Serine --> Pyr requires PLP. Then PLPSB removes ___ to make it stable.
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H+
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Which AA need PLP to help become pyruvate?
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All four!!
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THF stabilizes what?
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One C of glycine!
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What removes THF from the methyl?
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OH! It becomes OH on serine.
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2 Gly --> 1 Ser happens where?
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AA degredation and Photorespiration and DNA synth and anticancer drugs!
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Pterin is a ___ containing molecule used as "___" used in war.
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m-THF; sulfa drugs
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Serine Hydroxymethyl Transferase plays a key role in
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Folate metabolism! (Not just AA degred to pyr)
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Folates are requried for
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Photorespiration, DNA synth
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Folates are __ C compounds and deficiency causes
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1; Spina bifida(bottom of spine) or Anencephaly (top of spine)
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Can humans make folates? Bacteria?
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No; Yes
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Folate synthesis inhibitors are
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Antibiotics..."sulfa drugs"
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THF stabilizes what?
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One C of glycine!
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What removes THF from the methyl?
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OH! It becomes OH on serine.
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2 Gly --> 1 Ser happens where?
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AA degredation and Photorespiration and DNA synth and anticancer drugs!
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Pterin is a ___ containing molecule used as "___" used in war.
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m-THF; sulfa drugs
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Serine Hydroxymethyl Transferase plays a key role in
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Folate metabolism! (Not just AA degred to pyr)
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Folates are requried for
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Photorespiration, DNA synth
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Folates are __ C compounds and deficiency causes
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1; Spina bifida(bottom of spine) or Anencephaly (top of spine)
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Can humans make folates? Bacteria?
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No; Yes
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Folate synthesis inhibitors are
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Antibiotics..."sulfa drugs"
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If you do not have enough Phe hydroxylase, you will get
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Phenylketonuria (PKU)
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If you have PKU you should not eat
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Phe products! Such as Nutrasweet!
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Threonine -->
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Glycine (Serine Hydroxymethyl transferase)
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2 Glycine -->
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Serine (THF + Serine Hydroxymethyl Transferase)
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Alanine-->
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Pyruvate (TA..alpha KG needed)
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Serine -->
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Pyruvate (Serine dehydratase..releases NH3)
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To make PLP Schiff base resonance stabilized,
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remove H, R, or COO
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Thre-->Gly requires PLP. Then PLPSB removes ___ to make it stable
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R group
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Serine --> Pyr requires PLP. Then PLPSB removes ___ to make it stable.
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H+
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Which AA need PLP to help become pyruvate?
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All four!!
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Arg->Ornithine releases
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Urea
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Orn --> Glu-5-semiald is what type of rxn?
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TA
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Glu-5-semiald -->Glu is what type of rxn? What does it require?
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Redox; NAD(P)+
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Glu-> alpha KG uses what enzyme? What does it release?
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Glu DH and it releases NH3
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Gln --> Glu requires? Releases?
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water; NH3
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Asn --> Asp uses what enzyme? What does it require? Release?
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L-asparaginase; H2O; NH4+
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Which to AA's are involved with PKU?
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Tyr and Phe
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Pyr --> Ala is what type of rxn?
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TA. Requires AA and releases alpha Keto acid
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OXAL -> Asp is what type of rxn? What does it require? Release?
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TA; AA; alpha keto acid
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Asp->Asn uses what enzyme? What does it require? Release?
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Asn synthetase; Gln + ATP; Glu + AMP + PPi
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Why is Gln used in Asn synthesis?
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Because ammonia is a toxic gas and it supplies the NH2
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alpha KG -> Glu is what type of rxn? What does it require? release?
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TA; AA; Alpha keto acid
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Glu -> y-glu-P Int.(aka Glu-5-P) requires what enzyme? What does it require? Release?
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Glutamine synthetase; ATP; ADP
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y-Glu-P (aka Glu-5-P) -> Gln requires? Releases?
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NH4+; Pi
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Gln synthetase is a key enzyme in N meta. T/F
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True
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Gln synthetase is a key metabolic control point T/F
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True
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In bacteria, Gln Syn has ___ subunits and is regulated by ___.
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12 (2 layer donut); Adenylation
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In bacteria only, Gln Syn is well-regulated by adenylation which is regulated by ___ which is regulated by other things.
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Uridylyl Transferase
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In humans, Gln synthetase is not regulated by adenylation T/F
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True
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How many subunits do human Gln Syn have?
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8
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Analogs of what are good drugs for TB?
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y-Glutamylphosphate Int. (AKA Glu-5-P)
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Glycine is made from ___ using what enzyme?
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Threonine; Serine hydroxy methyl transferase
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Pro and Arg are made from what AA?
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Glutamate
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Glu -> Glu-5-P requires? releases?
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ATP; ADP
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Glu-5-P -> Glu-5-semiald require? releases?
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NAD(P)H; NAD(P)+ and Pi
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Glu-5-Semiald -> Delta-pyrroline-5-carboxylate is what type of rxn?
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Nonenzymatic
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delta-pyrroline-5-carboxylate -> Proline requires? Releases?
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NAD(P)H; NAD(P)+
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Glu-5-Semiald -> Ornithine is what type of rxn? Requires? Releases?
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TA; Glu; alpha KG
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Ornithine -> Arg via
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Urea Cycle
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Glu-5-P (AKA y-Glu-P Int) is found in what paths?
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During Arg and Pro synth as well as Gln synthesis.
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Arg -> Ornithine is how many steps?
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one
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What reduces delta pyrroline-5-carboxylate?
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NAD(P)H
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Gly + succinyl-CoA -->
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heme
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How do you make heme?
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Gly + succinyl CoA
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What happens if you have a def. of Uroporphyrinogen III synth?
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Red urine, red/brown teeth, light sens.,hairy
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What happens if you have a def of Porphobilinogen deaminase?
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Accum of ALA and PGB, abdom pain, red urine, neuro dysfun, King Geo III
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ALA is made by the addition of ___ and ___forming ____.
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Glycine; succinyl-CoA; PLP SB
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PBG is made with two ___ and forms ____.
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ALA; PLP SB
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N + ketone ->
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Schiff base
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Bruises change from
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Red->blue/purple -> green -> yellow/brown
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What causes color change on bruises?
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Heme degradation
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What color is heme? Biliverdia? Biliruben? Stercobilin? Urobilin?
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Red;Green; yellow/brown; Brown; Yellow
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Biliverdia is _____ heme. It is not ______.
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linear; oxygenated
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Biliruben is ____. How do you increase its solubility?
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insol.; Add sugars. Then excreted in bile. (Which is excreted in gut)
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If you accumulate Bilirubin in your eyes and skin you have
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Jaundice
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What is Jaundice?
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Inc heme deg.; liver disease, blocked bile duct, premature babies, cant add sugar to bilirubin, UV light is good
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PLP is used to remove ___ from AA's.
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Carboxyl group
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What do you use to remove R-group from AA's?
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Serine Hydroxymethyl transferase
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____ is a major inhibitory neurotransmitter in the brain. It makes you mellow.
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GABA
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How do you make GABA? What does it require? Release?
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Glu -> GABA; PLP; CO2
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Serotonin is made from _____. Requires? It is a ____.
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Trp; PLP and BH4!!; neutransmitter
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Serotonin is involved with
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smooth musc contr, cent nerv sys, anger, aggression, body temp, mood, sleep, vomiting, sex, appetite
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BH4 is a
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Terin ring
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BH4 is used for
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Phe -> Tyr; Trp -> 5HTP -> sero; Tyr -> L-DOPA
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L-DOPA, Dopamine, and epinephrine are all made from what AA?
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Tyr
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Melanin is involved with pigment. It is what color?
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red and black (skin and hair)
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If you have low dopamine you will get
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Parkinson's disease (shake)
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epinephrine causes an increase in ___which causes inc in _____.
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cAMP; glycogen breakdown
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NO is a stable free radical T/F
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True
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NO rapidly diffuses across membranes T/F
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True
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NO + superoxides-->
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help kill pathogens in white blood cells
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If you have a sustained release of NO you will
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go into endotoxic shock. It causes excessive damage after strokes.
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NO is a __.
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Vasodilator (relaxes blood vessels)
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NO is involved with ______.
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erections (Viagra)
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What is taken for heart problems because it releases NO as a byproduct?
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Nitroglycerin
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NO synthesis is a shortcut across the ___.
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Urea Cycle
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Arginine -> Hydroxyarginine requires? Releases?
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NADPH and O2; NADP+ and H2O
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Hydroxyarginine -> Citrulline + NO requires? Releases?
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1/2 NADPH + O2; 1/2 NADP+ + H2O
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NO synthesis is a shortcut between which to molecules in the urea cycle?
|
Arg -> Citrulline
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Free radicals play key roles in biological systems T/F
|
True
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Lightning does how much of N Fixation? Haber-Bosch processes? Biological N fixation?
|
10%; 50%; 40%
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What is the Haber-Bosch method to fix N?
|
N2 + 3H2 -> 2NH3...500deg C...300atm press, iron cat, uses 1% worlds energy
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If you build up too much Phe, you need PLP to turn it into
|
Phenylpyruvate which goes to urine
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Tyr -> L-DOPA uses what enzyme?
|
Tyr Hydroxylase
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L-DOPA -> Dopamine uses what enzyme? What does it require?
|
Aromatic AA decarboxylase; PLP
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Dopamine -> norepinephrine -> epinephrine...t/f
|
True
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What enhances epinephrine?
|
caffeine
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What causes a signaling molecule to release GDP and bind GTP?
|
epinephrine
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Draw Malonyl CoA
|
.
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Draw Serine
|
.
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Does Gln Syn have a low or high Km for ammonia? Is it reversible?
|
low; No
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Glu Synthetase is aka
|
GOGAT
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Is Glu DH reversible? Does it have a high or low Km for NH3? Glu? What is it good for?
|
yes; high;high;cleaves xs Glu and sends NH3 to urea cycle.
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Why is Glu DH not used for N assimilation?
|
Has too high of a Km for NH3.. it needs to find and bind quickly and irrev. It does neither!
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What is used instead of Glu DH for N assimilation?
|
Gln and Glu synthetase
|
