Lectures 33-34: Amino Acid Metabolism Flashcards
(37 cards)
What enzyme is involved in the transamination reaction of amino acid to form glutarate (step 1) during formation of ammonium ion?
Aminotransferase
What reaction occurs as nitrogen is liberated from an amino acid to become free ammonium ion (step 2)?
Deamination
Where does the urea cycle occur?
The liver
Ketogenic amino acids
Give rise to ketone bodies or fatty acids; degraded to Acetyl CoA or Acetoacetyl CoA
Which amino acids are STRICTLY ketogenic?
Leucine, lysine
Glucogenic amino acids
Give rise to glucose and have metabolic fates within the TCA cycle - all amino acids are glucogenic except leucine and lysine
Which amino acids are both glucogenic and ketogenic?
phenylalaine, tryptophan, tyrosine, isoleucine
Which amino acids are metabolically fated to pyruvate?
Alanine, cysteine, glycine, serine, threonine, tryptophan
Which amino acids are metabolically fated to oxaloacetate?
Asparagine, aspartate
Which amino acids are metabolically fated to fumarate?
aspartate, phenylalanine, tyrosine
Which amino acids are metabolically fated to succinyl-CoA?
Isoleucine, methionine, threonine, valine
Which amino acids are metabolically fated to alpha ketoglutarate?
arginine, glutamine, glutarate, histidine, proline
Which amino acids are metabolically fated to Acetyl CoA?
Isoleucine, leucine, tryptophan
Which amino acids are metabolically fated to Acetoacetyl CoA?
Leucine, lysine, phenylalanine, tryptophan, tyrosine
What is the rate determining step in heme synthesis?
Conversion of Succinyl CoA and glycine to delta aminolevulinate via Ala-synthase enzyme
Where does the rate determining step of heme synthesis occur?
Mitochondria
Where do all other reactions of heme synthesis occur (besides rate determining step)?
Cytosol
Acute intermittent porphyria is associated with which enzyme of heme synthesis?
Porphobilinogen deaminase
Congenital erythropoeitic porphyria is associated with which enzyme of heme synthesis?
Uroporphyrinogen III synthase, cosynthase
What are some physical conditions associated with porphyrias?
Skin problems, nervous/neuropsychiatric problems
What are the products of heme degradation?
Biliverdin which is converted to indirect/unconjugated bilirubin
What enzyme is responsible for converting unconjugated bilirubin to bilirubin?
UDP Glucuronide Transferase
What is the ultimate fate of bilirubin?
Excreted in urine as urobilinogen or feces as circobilin
What is the amino acid precursor of Sphingosine?
Serine
