Amino Acids

  1. what is phenylketonuria
    • occurs in newborns when they lack the enzyme (phenylalanine hydroxylase) to convert amino acid phenylalanine to tyrosine. 
    • phenylalanin is toxic to brain cells and accumulates in the blood
  2. amino acid in an acid pH will have what charge?
  3. amino acid in a basic pH will have what charge?
  4. what is the zwitterion form of an amino acid
    • dipolar form
    • contains both + and - charge
  5. what are the amino acids humans can't synthesize
    • leu
    • ile
    • val
    • met
    • phe
    • trp
    • thr
    • lys
    • his
    • arg
  6. enzyme defects affected by tyrosine aminoacidopathy and how is it tested?
    • enzyme defects: FAAH, TAT, 4- HPPO
    • test: mass spec
  7. PAH enzyme defect leads to what aminoacidopathy and how is it tested?
    • aminoacidopathy: PKU
    • test: mass spec, BIA
  8. what aminoacidopathy is called by enzyme defect of HGO
  9. what are the 3 screening newborns for PKU?
    • BIA (bacterial inhibition assay)
    • fluorometric analysis
    • mass spec
  10. describe BIA
    • incorporating B. subtilis spores in an agar plate with B-theinylalanine. B-theinylalanine is a metabolic inhibitor to B. subtilis growth. A filter disc with blood is placed on agar. A growth would occur if the phenylalanine exceeds the range of 2-4 mg/dL. 
    • Phenylalanine counteracts the antagonist and allows growth to occur
    • produce a lot of false positives
  11. how is fluorescence used to screen for PKU?
    • using the fluorescence of phenylalanine ninhydrin copper in the presence of dipeptide
    • produce fewer false positives than BIA
  12. how is mass spec used to obtain phenylalanine and tyrosine levels
    • using the ratio between phe/tyr to determine the phe levels
    • produce fewer false positives than BIA
Card Set
Amino Acids
-phenylketonuria -tyrosine -anode -cathode