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Flashcards

Nucleo. and AA

Amanda H English 105 cards

Cards in this deck (105)

  1. 1phenylketonuriadeficient in enzyme: phenylalanine hydroxylase
  2. 2phenylalanine hydroxylaseturns Phe into Tyr to become glucogenic or ketogenic intermediates
  3. 32nd pathway for PheMakes phenylpyruvate -->
    which turns into phenylacetate and phenyllactate
  4. 4PKU will lead to excess __ in plasma and urinePhenylpyruvate, Phenylacetate and Phenyllactate
  5. 5physiological effect of PKUthe secondary pathway products will compete for the transporter that carries Phe across the BBB
  6. 6Treatment for PKUdietary restriction of Phe and no aspartame (contains Phe)
  7. 7Phe and albinismPhe is the precursor to Tyr which can turn into melanin. No Phe = no melanin
    therefore, loss of pigmentation
  8. 8branched chain AALeucine, Isoleucine, Valine
  9. 9Enzymes needed to catabolize branched chain AA1. Branched chain aminotransferase
    to make a-keto acids
    2. branched chain a-keto acid dehydrogenase complex
    to make acyl coa derivatives
  10. 10mutation in branched chain a-keto acid DH complexmaple syrup disease --build up on a-keto acids and neuro diseases that will affect uptake of Val, Ile, Leu
  11. 11Factors needed for the a-keto acid DH complexNAD, CoA SH, makes Co2
  12. 12Where are carbon and nitrogen atoms derived from?Glycine and Succinyl CoA (int of CAC)
  13. 13Porphyrinscyclic products that bind primarily to Fe2+ or Fe3+ (ex: heme)
  14. 14constituents of Porphyrinscontains 4 pyrrole rings
    -they have different sidechains based on the type of porphyrin
  15. 15synthesis of porphyrins occurs where?In the mitochondria and the cytosol
  16. 16Porphyriasgenetic disease that leads to defect in synthesis of porphyrins and accumlation of the intermediates
  17. 17Acute intermittent porphyriaabdominal pain, motor weakness
    only need to inherit one defective allele
    see symptoms after fasting or not eating enough CHO
    -build up of non fluorescent intermediates
  18. 18Porphyria cutanea tarda-red urine, teeth fluoresce, skin is sensitive to light, anemia
    -fluorescent intermediates and non fluorescent int accumulate
  19. 19examples of catecholaminesDopamine, norepinephrine (neurotransmitters), and epinephrine
    --All synthesized from Tyr
  20. 20Histaminestrong vasodilator
    -formed by decarboxylation of His
    -mediates responses (allergic, inflammatory, gastric acid secretion)
  21. 21Serotonin-mostly in intestinal mucosa. also in CNS
    -"feel good" neurotransmitter
    -in brain can turn into melatonin
    -all synthesized from Trp
  22. 22Melatoninmaintains circadian rhythm
    -Trp--> Serotonin --> Melatonin (in the brain)
  23. 23Creatine and ATPCreatine phosphate (phosphocreatine) is high energy and found in muscle.
    -can replenish ATP stores by phosphorylating ADP
  24. 24Creatine synthesisGlycine takes guanidino group from Arg and the methyl group from Met
  25. 25Monosodium glutamateWhen enters the body, will become only Glu
    -will be efficiently metabolized and form a-KG which will be oxidized by the CAC
  26. 26Amino acid pool gets AA from...Protein turnover, dietary protein intake, amino acid biosynthesis
  27. 27use AA for:synthesis of proteins, synthesis of nitrogenous molecules, degradation of AA used to make ketone bodies, FA, steroids, glucose from backbone
  28. 28protein turnoverremoves damaged or excess proteins
    -300-400g/day
    half life depends on the function
  29. 292 ways to degrade proteins1. Ubiquitin proteasoome
    2. Chemical signals
  30. 30Ubiquitin proteasome pathway (intracellular)Ubiquitin links to Lys residues then gets recognized by proteasome which will break down the protein into peptides and then release the ubiquitin molecules
  31. 31Dietary protein digestiontoo large to absorb intact proteins so gets broken down into AA, dipeptides, tripeptides
    -about 70-100 g/day
  32. 32proteolysishydrolytic cleavage of proteins by proteases in the stomach and small intestine
    -cleaves after carbonyl and before N
  33. 33Protein digestion: Mouthchew food to increase the surface area and make the proteins more accessible
  34. 34Protein digestion: StomachGastric juice has low pH (1.5-2)
    HCl will denature proteins by breaking the salt bridges or H-bonds and then Pepsin will cleave them into AA or short peptide chains
  35. 35Protein digestion: Small intestinePancreatic juice secretes enzymes
    HCO3 neutralizes stomach pH so cells aren't damaged
    -Neutral pH lets other enzymes function
  36. 36After digested in sm. intestine:___the AA are absorbed into endothelial cells and go into the blood and to the liver and periphery via portal vein
  37. 37K+/H+ pump in endothelial cells-ATP hydrolysis (active transport)
    -pumps H+ into stomach for HCl
    -releases heat
    -these ATPases surface when eating
  38. 38CFTR in endothelial cellspumps Cl- ions into the stomach for HCl
  39. 39GERDgastro-esophageal reflux disease
    1. too much acid in the stomach
    2. malformed sphincter (causes acid reflux)
  40. 40Histamine receptor in endothelial cellsHistamine is released by chewing. Will bind to the receptor and activate cAMP and PKA which will phosphorylate the H+/K+ ATPase to move it to the apical surface
  41. 41Antacids (tums)will neutralize the pH in the stomach
  42. 42Histamine H2 receptor blockers (zantac)will lower cAMP activity so PKA can't phosphorylate ATPase as much
  43. 43Proton pump inhibitor (Prevacid)directly influences the H+/K+ ATPase so it is less active
  44. 44Zymogensall proteolytic enzymes are secreted as inactive zymogens --will become active by proteolysis
    -after cleavage, can conform into protein
  45. 45Pepsinogen activation to PepsinAutocatalytic at low pH: will be slowly cleaved in stomach at low pH and Pepsin itself can cleave more pepsinogens
  46. 46Exopeptidase (protease)works from the end of a protein (N or C terminus) to cleave
    -Ex) carboxypeptidase: breaks down at C terminus
  47. 47Endopeptidase (protease)Works on the inside of the peptide chain
    ex: Trypsin cleaves bonds after Arg or Lys residue
  48. 48Proteases will self inactivate!.
  49. 49what are the transdeamination reactions1. transamination
    2. oxidative deamination
  50. 50TransaminationAmino acid + a-ketoglutarate
    ==> L-glutamate + corresponding a-keto acid
    by enzyme: amino transferase
  51. 51Amino transferasesSpecific for each AA
    need coenzyme PLP (pyridoxal phosphate) from vit B6
  52. 52Oxidative deaminationL-glutamate turns into a-ketoglutarate and releases the ammonium (NH4+)
    enzyme: Glutamate dehydrogenase
  53. 53Urea CycleThe NH4 released by transdeamination reactions combines with Aspartate and HCO3- to make urea (series of reactions)
  54. 54Transamination doesn't occur for which AA?Glutamate, Lysine, Threonine
  55. 55Amino acid and a-keto acid pairs1. Pyruvate & Alanine
    2. Oxaloacetate & Aspartate
  56. 56Glutamate in the liverGlutamate dehydrogenase breaks down glutamate into a-keto glutarate and NH4+
  57. 57Why is NH4 released in the mitochondria of the liver?So that is it compartmentalized and doesn't get into blood
  58. 58Glutamate dehydrogenaseneeds NAD+ or NADP+
    Allosteric enzyme, modulators:
    Activated by high ADP
    Inhibited by high GTP
  59. 59Ammonium in most non-liver tissues:NH4+ + glutamate --> glutamine
    enzyme: glutamine synthetase (ATP cleavage)
    Gln goes to the liver by blood
  60. 60Glutamine from non liver tissues reaches the liver and __Glutaminase will cleave off the NH4 to make glutamate
  61. 61Ammonium in muscle tissues (Glucose-Alanine cycle)Glutamate will build up from aminotransferase activity
    -glutamate gives NH4+ to pyruvate --> Alanine and a-ketoglutarate
    -Alanine will go to the liver for transdeamination
  62. 622nd reaction of NH4+ in muscle tissuesGlutamine is made by glutamine synthetase (similar to non muscle tissues) and is released from muscles to the liver by blood
  63. 63Precursors of Urea1. CO2 --found in form of HCO3-
    2. NH4+ free ammonium released by GluDH in mitochondria
    3. NH4+ from Aspartate
  64. 64Uncatalyzed breakdown of ureawill slowly turn into Nh3 and H20 and NHCO
  65. 65Catalyzed urea breakdownenzyme: Urease ( then hydrolysis)
    -fast reaction that takes 2 steps
  66. 66Carbamoyl phosphate synthetase I1st step of urea synthesis
    HCO3- + NH4+ = carbamoyl phosphate
    (need to hydrolyze 2 ATP)
    Need N-acteylglutamate (allosteric actvator-need this to have ANY activity)
  67. 67N-acetyl glutamate synthaseGlutamate + Acetyl CoA = N-acetylglutamate
    need arginine --allosteric activator
  68. 68regulation of CPS-Idietary protein--AA--increase NH3(need to make urea)--produce more N-acetylGlu--activates CPS-I
  69. 69what does Glutamate dehydrogenase do?Makes free NH4+ by breaking down glutamate into NH4+ and a-ketogluterate
  70. 70Formation of AspGlutamate +oxaloacetate = aspartate + a-ketogluterate
    -The Asp will give the second amino group to form urea
  71. 71enzymes 2-4 are clustered in urea cycle-Rapid reaction rate
    -intermediates are close in the complex
    -high concentration of intermediates
    -side chains won't undergo reactions
  72. 72ArginaseCleaves the urea off of the arginine --> urea+ornithine
  73. 73Kreb's bicycle--which intermediates link together CAC and Urea cycle?CAC and urea cycle are linked by:
    1. Aspartate-made in CAC turns into int of urea cycle (argininosuccinate)
    2. this will make Fumarate which will turn into malate and enter the CAC
  74. 74Overall reaction of urea synthesisAsp + NH3 + HCO3- + 3 ATP --> urea +fumarate + 2 ADP + AMP + 2Pi+ PPi (high E)
    energy cost = 3 ATP
    --but 4 high energy bonds (including PPi)
  75. 75AmmoniotelicAquatic animals will release NH3 directly into the water around them
  76. 76UreatelicMammals who use kidneys to release urea in the urine
  77. 77UricotelicProduces Uric acid--not very soluble in water-a crystallized structure that is used in birds and reptiles
  78. 78Free NH4+ comes from 4 things1. breakdown of dietary protein
    2. kidney uses Glu and Gln
    3. Amines
    4. Purine/pyrimidine catabolism
  79. 79Which enzymes help the liver produce free NH4+?1. serine dehydratase
    2. threonine dehydratase
    3. glutaminase
  80. 80Where does NH3 come from?The breakdown of AA from diet or body proteins
  81. 81Neuroaminessource of nitrogen and NH4+
    ex) norepinephrine
  82. 82Purines and pyrimidinescatabolism of adenine, cytosine, guanine, thiamine will produce NH4+
  83. 83metabolism of NH4+ in kidney1. glutaminase = makes NH4+ and Glu
    then glutamate DH = makes NH4+ + a-ketoglutarate
    2. Glutamine can go to liver to be broken down to release NH4+
  84. 84How do you keep blood NH4+ levels low?1. Form urea in the liver
    2. form Glu in muscles using glutamate DH (reverse rxn)
    3. make Gln by glutamine synthetase
  85. 85HyperammonemiaWhen there is too much NH4+ in the body
    -will be damaging to the CNS
  86. 86How does the body compensate for hyperammonemia?increase glutamine synthesis using glutamate=high glutamine and low glutamate
  87. 87High glutamine in the bodyGln is an osmolyte for astrocytes so if there is too much, it will attract H2O and cause cerebral edema
  88. 88Low glutamate in the bodyGlu is a neurotransmitter and also a substrate to make GABA neurotransmitter
    -will decrease and affect neurotransmitter activity if depleted
  89. 89Causes of hyperammonemia1. liver damage --can't make urea to excrete
    2. Congenital form--mutation in 1/5 genes (need to have defects in both alleles
  90. 90Acquired hyperammonemia1. Liver damage from hepatitis or hepatotoxins
    2. Cirrhotic-colateral circulation of scar tissue develops and NH4+ will bypass the liver because blood will not flow there
  91. 91Congenital hyperammonemia affects which enzyme?Arginase defects -this is the last step of the cycle and although urea isn't produced, arginine can still exit through the urine
  92. 92Congenital hyperammonemia treatmentinhibit protein intake and increase Kcal/day of CHO to reduce AA catabolism.
    -Some drugs can bind to AA so they will be excreted by urine instead of being metabolized.
  93. 93Glucogenic AAcarbon backbone of AA --> pyruvate or an intermediate of the CAC
    -can potentially be used for gluconeogenesis
  94. 94Ketogenic AAAA catabolized into Acetyl CoA or acetoacetate (ketone body)
    -does not give rise to net synthesis of glucose
    -can form FA, ketone bodies/precursors
  95. 95Which AA are exclusively ketogenic?Lysine
    Leucine
  96. 96Glucogenic and ketogenic AA?Tryptophan
    Tyrosine
    Threonine
    Phenylalanine
    Isoleucine
  97. 97which macromolecules can lead to glucose synthesis?Proteins and CHO.
    Not FA
  98. 98Which AAs can make Pyruvate via amino transferasesTryptophan
    Alanine
    Cysteine
    Serine
  99. 99Which AA make oxaloacetate (glucogenic)Asparigine turns into Aspartate (aspariginase)
    Aspartate turns into oxaloacetate (aspartate amino transferase)
    In mitochondria
  100. 100Phenylalanine is the precursor to what molecules/AAMakes Tyrosine. (Phe hydroxylase)
    Tyr makes Fumarate (glucogenic) and Acetyl CoA (ketogenic)
  101. 101If Phe hydroxylase is defective...secondary pathway will become v. active
    produces phenylpyruvate --> phenylacetate and phenyllactate
    -these lead to PKU and compete for transporters of Phe therefore high levels of Phe in the tissues
  102. 102Branched AAValine, Leucine, Isoleucine
    Essential AA
  103. 103Catabolism of branched chain AA1. branched chain aminotransferases make the corresponding a-keto-acids
    2. branched chain a-keto acid dehydrogenase complex (needs NAD, CoA-SH) makes Acyl CoA derivatives and CO2
  104. 104mutation of branched chain a-keto acid dehydrogenase complex...This will result in a build up of a-keto acids =maple syrup disease (urine is sweet)
    will affect uptake of Val, Ile, Leu
  105. 105—

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Flashcards on Nucleo. and AA, created by Amanda H on 17/03/2016.
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