Proline, synthesis from glutamate

Fig. 2. Proline synthesis from glutamic acid. The details of the reactions are in Table ...

Proline is synthesized from glutamate in three steps. The second step is a spontaneous cyclization reaction. In arginine synthesis the acetylation of glutamate prevents the cyclization reaction. In mammals the reactions that convert ornithine to arginine are part of the urea cycle. 

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