Origins of Carbon Skeletons of the Amino Acids

BIOCHEMISTRY 3(2+1)
Lesson 24 : Amino Acid Metabolism

Origins of Carbon Skeletons of the Amino Acids

  1. Amino acids that must be supplied in diet are termed essential; others are nonessential.
  2. Although the biosynthesis of specific amino acids is diverse, they all share a common feature - carbon skeletons come from intermediates of glycolysis, PPP, or citric acid cycle.
  3. There are only six biosynthetic families:

    • Derived from oxaloacetate --> Asp, Asn, Met, Thr, Ile, Lys
    • Drived from pyruvate --> Ala, Val, Leu
    • Derived from ribose 5-phosphate --> His
    • Derived from PEP and erythrose 4-phosphate --> Phe, Tyr, Trp
    • Derived from a-ketoglutarate --> Glu, Gln, Pro, Arg
    • Derived from 3-phosphoglycerate --> Ser, Cys, Gly
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Last modified: Monday, 19 March 2012, 9:36 AM