Lysine catabolism

Summary
Organism
Homo sapiens (human)
Reactome
R-HSA-71064
PubChem
R-HSA-71064
Description
  • In humans, most catabolism of L-lysine normally proceeds via a sequence of seven reactions which feeds into the pathway for fatty acid catabolism. In the first two reactions, catalyzed by a single enzyme complex, lysine is combined with alpha-ketoglutarate to form saccharopine, which in turn is cleaved and oxidized to yield glutamate and alpha-ketoadipic semialdehyde. The latter molecule is further oxidized to alpha-ketoadipate. Alpha-ketoadipate is oxidatively decarboxylated by the alpha-ketoglutarate dehydrogenase complex (the same enzyme complex responsible for the conversion of alpha-ketoglutarate to succinyl-CoA in the citric acid cycle), yielding glutaryl-CoA. Glutaryl-CoA is converted to crotonyl-CoA, crotonyl-CoA is converted to beta-hydroxybutyryl-CoA, and beta-hydroxybutyryl-CoA is converted to acetoacetyl-CoA. The products of lysine catabolism are thus exclusively ketogenic; i.e., under starvation conditions they can be used for the synthesis of ketone bodies, beta-hydroxybutyrate and acetoacetate, but not for the net synthesis of glucose (Cox 2001; Goodman and Freeman 2001).
Click on a node on the pathway to see its details. Glycoproteins are marked with a glycoprotein icon in their name.
Displaying all 2 entries
UniProt ID Protein Name Gene Symbol Pathway Viewer
P49419 Alpha-aminoadipic semialdehyde dehydrogenase
  • ALDH7A1
  • ATQ1
view
Q14894 Ketimine reductase mu-crystallin
  • CRYM
  • THBP
view

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Acknowledgements

Supported by JST NBDC Grant Number JPMJND2204

Partly supported by NIH Common Fund Grant #1U01GM125267-01


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