This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
|Superclasses:||Biosynthesis → Amino Acids Biosynthesis → Proteinogenic Amino Acids Biosynthesis → L-proline Biosynthesis|
Expected Taxonomic Range: Viridiplantae
In plants proline can be synthesized from either glutamate [ L-proline biosynthesis I] or ornithine [ L-proline biosynthesis III]. In addition to the route from ornithine to proline described in [ L-proline biosynthesis III] (via L-glutamate-5-semialdehyde and (S)-1-pyrroline-5-carboxylate), an additional route is believed to exist, as depicted in here.
In this alternative ornithine route, the α-amino group of ornithine is lost, (opposed to the δ-amino group in the other route), giving rise to 2-keto-ornithine, which is then converted to proline via 1-pyrroline-2-carboxylate.
This existence of this pathway is supported by radio tracer experiments. No information is available about the enzymes or genes of this pathway in plants.
Variants: L-arginine degradation VI (arginase 2 pathway), L-ornithine degradation I (L-proline biosynthesis), L-proline biosynthesis I, L-proline biosynthesis II (from arginine), L-proline biosynthesis III
Watanabe14: Watanabe S, Tanimoto Y, Yamauchi S, Tozawa Y, Sawayama S, Watanabe Y (2014). "Identification and characterization of trans-3-hydroxy-l-proline dehydratase and Δ(1)-pyrroline-2-carboxylate reductase involved in trans-3-hydroxy-l-proline metabolism of bacteria." FEBS Open Bio 4;240-50. PMID: 24649405
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