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70 Cards in this Set
- Front
- Back
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What are the classifications of a.a?
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1. Glucogenic, ketogenic
2. Essential and non-essential |
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What are the essential a.a.s?
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Histidine, methionine, threonine, valine, isoleucine, phenylalanine, tryptophan, leucine, lysine
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What are the essential glucogenic amino acids?
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Histidine, methionine, threonine, valine
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What are the essential a.a that are both glucogenic and ketogenic?
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Isoleucine, Phenylalanine, Tryptophan
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What are the ketogenic amino acids?
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Both are essential
Leucine Lysine |
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What a.a. are both glucogenic and ketogenic?
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Tyrosine, Isoleucine, Tryptophan, Phenylalanine
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What amino acids form oxaloacetate?
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1. Asparagine
2. Aspartate |
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What does asparaginase do?
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Hydrolzes asparagine to aspartate
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How do Glu and Gln form alpha-ketoglutarate?
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Glu: Glutamate dehydrogenase
Gln: Gln to Glu via glutaminase, then Glu to alpha-KG |
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How does proline form alpha-ketogluatarate?
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Proline is oxidized to form Glu, Glu to alpha-KG
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How does arginine form alpha-KG?
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Arg to ornithine (arginase) to alpha-KG
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How does Histidine form alpha-KG?
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His to Urocanic acid via histidase, to N-formiminoglutamate (FIGlu) to Glutamate (uses FH4), Glu to alpha-KG
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What a.acids form alpha ketoglutarate?
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Glu, Gln, His, Pro, Arginine
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What is converted to Glu in the liver?
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Pro, Arg, Ornithine
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What happens to Glu in the liver?
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Glu in deaminated in liver, intestines, kidney, rest sent for glucose generation
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What reaction is used to test for folate deficiency?
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FIGlu conversion to glutamate requires FH4, so testing for FIGlu would show if there is a deficiency in FH4
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What is histidinemia?
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Deficiency in histidase, results in inability to metabolize histidine
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What a. acids form pyruvate?
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Alanine, Cys, Serine, Glycine, Threonine
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How does alanine form pyruvate?
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transamination via aminotransferase (paired with glutamate and alpha-KG)
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How does Cys form pyruvate?
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desulfuration
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How does glycine become pyruvate?
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Glycine to serine (serine hydroxymethyltransferase), serine to pyruvate (serine dehydratase)
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How is threonine related to serine and glycine?
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Threonine can become glycine + AcCoA, glycine + C can become serine
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How is glycine involved in kidney stones?
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Glycine becomes glyoxylate, which becomes oxalate
Oxalate build up= kidney stones |
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What causes nonketotic hyperglycinemia?
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deficiency in glycine cleavage enzyme
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What a.acids form fumarate?
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Phenylalanine, Tyrosine
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Are phenylalanine and tyrosine glucogenic, ketogenic or both?
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Both
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What is phenylketonuria (PKU)?
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mutation in PAH causes buildup of Phe, Phe converted to phenylketone (seen in urine)
Causes mental retardation |
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What is alkaptonuria?
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Black urine, problem with degredation of tyrosine
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What is albinism?
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Defect in tyrosinase, no melanin, no pigment
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What is Type I Tyrosinemia?
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accumulation of tyrosine bc problem with final stage of breakdown, causes skin and neuro problems
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What enzymatic deficiency causes PKU?
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Phenylalanine hydroxylase
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What is the prevalence of PKU?
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1:15,000
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What are the effects of Phe and Tyr levels with PKU?
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Phe is raised because PKU blocks the conversion of Phe to Tyr, therfore increase Phe and less Tyr
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What is seen in hyperphenylalanemia?
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Increased Phe in serum
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How does BH4 or BH2 reductase deficiency influence Phe and Tyr levels?
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BH4 is a cofactor for conversion of Phe to Tyr, a deficiency in BH4 or BH2 reductase would increase serum Phe levels bc it could not be converted to Tyr
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What is BH2 reductase?
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Converts BH2 to BH4
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What influences does a deficiency in BH2 reductase have?
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1. Increased Phe (less conversion to Tyr)
2. Decreased catacholamines (less Tyr, less DOPA b/c BH4 is cofactor in conversion of Tyr to DOPA) 3. Less seratonin (increased Tryptophan) bc BH4 is cofactor |
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What are symptoms of PKU?
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1. Elevated Phe, urine is musty odor
2. CNS symptoms (low IQ, mental retardation, failure to grow) 3. Hypopigmentation (light hair, skin, blue eyes) |
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Why is there hypopigmentation in PKU?
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Lack of tyrosine, tyrosine is converted to melanin
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What is required for a diagnosis of PKU? What is normal?
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plasma phe level of 20 mg/dL
Normal 0.5 mg/dL |
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How is PKU inherited?
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Recessive
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What are the mandatory screening tests in infants?
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1. Ferric Cl urine test for phenylpyruvate
2. Blood phe levels 3. Guthrie bacterial inhibition test |
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What is the Guthrie bacterial inhibition assay?
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PKU blood supports the growth of phenylalanine-dependent bacteria
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What enzyme does PKU effect?
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phenylalanine hydroxylase
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What enzyme does albinism effect?
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Tyrosinase
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What enzyme does Alkaptonuria effect?
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Homogentisate oxidase
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What is the symptom triad for alkaptonuria?
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1. Dark urine
2. Ochronosis 3. Arthritis |
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What enzyme does Type I tyrosinemia effect?
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Fumarylacetoacetate hydrolase
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What disease causes cabbage-like smell and liver failure?
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Type I tyrosinemia
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What is the treatment for alkaptonuria?
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decrease phe and tyr in diet
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What a. acids form succinyl CoA?
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Met, Threonine, Val, Isoleucine
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What can Thr be converted to ?
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Pyruvate, succinyl-CoA
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How does Thr become succinyl CoA?
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deaminated to alpha-KB, then converted to propionyl CoA, then to succinyl-CoA
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How is homocysteine degraded?
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1. conversion to methionine via B12 and N-methyltetrahydrofolate
2. Conversion to cystein via B6 |
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How is homocysteine related to CVD?
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Increase homocysteine= increased CVD
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What a. acids form acetyl CoA or acetoacetyl CoA?
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Leu, Ile, Lys, Trp
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Is trp ketogenic or glucogenic, or both?
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both
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What part of Trp is ketogenic?
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the indole is coverted to acetoacetyl-CoA, which then goes to ketogenesis
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What part of Trp is glucogenic?
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the main chain becomes alanine which undergoes gluconeogenesis
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What is the process of catabolism for branched chain a.a.?
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1. Transamination
2. Oxidative decarboxylation 3. Dehydrogenation |
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Where is the deficiency in classic maple syrup urine disease?
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deficiency in BC alpha-keto acid dehydrogenase activity, which means the alph-ketoacids do not undergo oxidative decarboxylation
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What the the procedure for screening and diagnosis of MSUD?
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antenatal diagnosis and neonatal screening
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Treatment of MSUD?
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Synthetic formula with limited branched chain a.a.
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What is the deficiency that causes Albinism? What is affected?
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Tyrosinase; Tyrosine metabolism is affected
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What is the deficiency that causes Alkaptonuria?
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Homogentisate dioxygenase; Phe and Tyr metabolism is affected
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What is the deficiency that causes Cystathioninuria?
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Cystathionase; cysteine, methionine, serine metabolism affected
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What is the deficiency that causes histidinemia?
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Histidase; histidine metabolism in affected
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What is the deficiency in homocystinuria?
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crystathionine synthase; cysteine, methionine, serine metabolism is affected
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What is the deficiency is MSUD?
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Branched chain keto acid dehydrogenase; valine, isoleucine and leucine metabolism is affected
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What is the deficiency in PKU?
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Phenylalanine hydroxylase; phenylalanine is not metabolized to tyrosine correctly
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