1-Pyrroline-5-carboxylic acid

Chemical compound From Wikipedia, the free encyclopedia

1-Pyrroline-5-carboxylic acid (systematic name 3,4-dihydro-2H-pyrrole-2-carboxylic acid[2]) is a cyclic imino acid. Its conjugate base and anion is 1-pyrroline-5-carboxylate (P5C). In solution, P5C is in spontaneous equilibrium with glutamate-5-semialdehyde (GSA).[3]

Quick facts Names, Identifiers ...
1-Pyrroline-5-carboxylic acid
Names
Preferred IUPAC name
3,4-Dihydro-2H-pyrrole-2-carboxylic acid
Other names
1-Pyrroline-5-carboxylic acid
δ-1-Pyrroline-5-carboxylic acid
P5C
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
KEGG
MeSH Delta-1-pyrroline-5-carboxylate
UNII
  • InChI=1S/C5H7NO2/c7-5(8)4-2-1-3-6-4/h3-4H,1-2H2,(H,7,8) checkY
    Key: DWAKNKKXGALPNW-UHFFFAOYSA-N checkY
  • InChI=1/C5H7NO2/c7-5(8)4-2-1-3-6-4/h3-4H,1-2H2,(H,7,8)
    Key: DWAKNKKXGALPNW-UHFFFAOYAB
  • C1CC(N=C1)C(=O)O
  • O=C(O)C1/N=C\CC1
Properties
C5H7NO2
Molar mass 113.115 g/mol
Acidity (pKa) 1.82/6.07[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 Â°C [77 Â°F], 100 kPa).
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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.[4][5][6]

In prokaryotic proline biosynthesis, GSA is synthesized from γ-glutamyl phosphate by the enzyme γ-glutamyl phosphate reductase.[7]

2D representation of the chemical structure of Q27102623.
L-γ-glutamyl phosphate
+ NADPH
 
 
H+
Pi
Reversible left-right reaction arrow with minor forward substrate(s) from top left, minor forward product(s) to top right, minor reverse substrate(s) from bottom right and minor reverse product(s) to bottom left
H+
Pi
 
2D representation of the chemical structure of Q2823261.
L-glutamate-5-semialdehyde
+ NADP+
 

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.[8][9] The enzyme pyrroline-5-carboxylate reductase converts L-P5C into proline.[10]

2D representation of the chemical structure of Q27105294.
L-P5C
+ NADH
 
 
H+
 
Reversible left-right reaction arrow with minor forward substrate(s) from top left and minor reverse product(s) to bottom left
H+
 
 
2D representation of the chemical structure of Q20035886.
L-proline
+ NAD+
 

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.[11]

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.[12] This allows an optimum level of proline to be produced from reduced nitrogen to control osmotic stress.

References

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