From glutamate: activate the side chain, reduce it to an aldehyde, close the ring, reduce again
Route: Glutamate → γ-Glutamyl phosphate → Glutamate 5-semialdehyde → 1-Pyrroline-5-carboxylate → Proline
The first two steps activate the side-chain carboxyl of glutamate with ATP, then reduce it with NADPH to an aldehyde. In humans one protein (P5C synthase) carries both activities; here they are shown as two enzymes, a kinase and a reductase. The aldehyde and the amino group of the same molecule meet and close a five-membered ring without any enzyme, giving 1-pyrroline-5-carboxylate (P5C) and water. Pyrroline-5-carboxylate reductase then reduces the ring double bond; it can use NADPH or NADH. The structures shown come from different species.
Practice this pathway All pathways
| Step | Enzyme | EC | In | Out |
|---|---|---|---|---|
| 1 | Glutamate 5-kinase (γ-glutamyl kinase) | 2.7.2.11 | ATP | ADP |
| 2 | γ-Glutamyl phosphate reductase | 1.2.1.41 | NADPH | NADP⁺, Pᵢ |
| 3 | Pyrroline-5-carboxylate reductase | 1.5.1.2 | NADPH | NADP⁺ |
Enzyme names and EC numbers are those used on the interactive board. Checked against sources: see the claim table in the repository (tools/pathway_data/checks).