1-Pyrroline-5-carboxylic acid

Biochemistry

The stereoisomer (S)-1-pyrroline-5-carboxylate (also referred to as L-P5C) is an intermediate metabolite in the biosynthesis and degradation of proline and arginine.

In prokaryotic proline biosynthesis, GSA is synthesized from γ-glutamyl phosphate by the enzyme γ-glutamyl phosphate reductase. In most eukaryotes, GSA is synthesised from the amino acid glutamate by the bifunctional enzyme 1-pyrroline-5-carboxylate synthase (P5CS). The human P5CS is encoded by the ALDH18A1 gene. The enzyme pyrroline-5-carboxylate reductase converts P5C into proline.

In proline degradation, the enzyme proline dehydrogenase produces P5C from proline, and the enzyme 1-pyrroline-5-carboxylate dehydrogenase converts GSA to glutamate. In many prokaryotes, proline dehydrogenase and P5C dehydrogenase form a bifunctional enzyme that prevents the release of P5C during proline degradation.

A reciprocal regulation of delta 1-pyrroline-5-carboxylate synthetase (P5CS) and proline dehydrogenase genes controls proline levels during and after osmotic stress in plants proportional to the level of proline. This allows an optimum level of proline to be produced from reduced nitrogen to control osmotic stress.

References

References

1. PubChem. "3,4-Dihydro-2H-pyrrole-2-carboxylic acid".
2. (1975-04-01). "Δ1-Pyrroline-5-carboxylate and Δ1-pyrroline-3-hydroxy-5-carboxylate: Chromatography on the amino acid analyzer". Analytical Biochemistry.
3. (2008-10-01). "Comparative Aspects of Tissue Glutamine and Proline Metabolism". The Journal of Nutrition.
4. (2015). "Role of proline and pyrroline-5-carboxylate metabolism in plant defense against invading pathogens". Frontiers in Plant Science.
5. (2015). "Physiological implications of arginine metabolism in plants". Frontiers in Plant Science.
6. (Oct 1996). "Assignment of the human gene encoding the delta 1-pyrroline-5-carboxylate synthetase (P5CS) to 10q24.3 by in situ hybridization". Genomics.
7. "Entrez Gene: ALDH18A1 aldehyde dehydrogenase 18 family, member A1".
8. (2017-10-15). "Structure, function, and mechanism of proline utilization A (PutA)". Archives of Biochemistry and Biophysics.
9. Verma, D.P.S. (December 1996). "Reciprocal regulation of delta 1-pyrroline-5-carboxylate synthetase and proline dehydrogenase genes controls proline levels during and after osmotic stress in plants". Molecular Genetics.