ornithine decarboxylase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: L-ornithine + H+ = CO2 + putrescine. [EC:4.1.1.17, RHEA:22964]

Ornithine decarboxylase (ODC) is an enzyme responsible for catalyzing the decarboxylation of L-ornithine to putrescine. This reaction is the first committed step in the biosynthesis of polyamines, which are essential for various cellular processes, including cell growth, proliferation, and differentiation. ODC is a pyridoxal phosphate-dependent enzyme that utilizes a mechanism involving Schiff base formation with the amino group of ornithine. The reaction involves the following steps: 1) Ornithine binds to the enzyme and forms a Schiff base with the pyridoxal phosphate cofactor. 2) The Schiff base undergoes a decarboxylation reaction, releasing carbon dioxide and forming a highly reactive intermediate. 3) The intermediate is protonated and undergoes a tautomerization reaction, resulting in the formation of putrescine. 4) Putrescine is released from the enzyme, completing the catalytic cycle. ODC activity is tightly regulated by a variety of factors, including substrate availability, product inhibition, and post-translational modifications. The enzyme is also subject to rapid turnover, with a half-life of only a few hours. This rapid turnover allows for a precise control of polyamine synthesis and is essential for maintaining cellular homeostasis.'
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Proteins (2)

Compounds (4)