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MetaCyc Enzyme: Δ1-pyrroline-4-hydroxy-2-carboxylate deaminase

Gene: lhpC Accession Number: G-16026 (MetaCyc)

Synonyms: PP_1257, 1-pyrroline-4-hydroxy-2-carboxylate deaminase

Species: Pseudomonas putida KT2442

Subunit composition of Δ1-pyrroline-4-hydroxy-2-carboxylate deaminase = [LhpC]8
         Δ1-pyrroline-4-hydroxy-2-carboxylate deaminase subunit = LhpC

This enzyme catalyzes the third step in the bacterial 4-hydroxy-L-proline degradation pathway (see trans-4-hydroxy-L-proline degradation II). It is a unique member of the dihydropicolinate synthase/N-acetylneuraminate lyase family. Its encoding gene is contained within the 4-hydroxy-L-proline degradation operon of this organism [Watanabe12].

Disruption of the gene encoding this enzyme lead to loss of growth on both L-hydroxyproline and D-hydroxyproline, but not L-proline and D-proline, suggesting the specificity of this pathway for 4-hydroxy-L-proline degradation [Watanabe12].

Recombinant His6-tagged enzyme was overexpressed in Escherichia coli and purified. The native apparent molecular mass was approximately 275 kDa by gel filtration chromatography. The subunit apparent molecular mass was 35 kDa by SDS-PAGE, which suggested a homooctamer [Watanabe12].

In earlier work on the Pseudomonas putida enzyme the native apparent molecular mass was determined by analytical ultracentrifugation to be 62 kDa. The subunit composition was not reported [Singh65a].

Map Position: [1,436,114 <- 1,437,061]

Molecular Weight of Polypeptide: 34.075 kD (from nucleotide sequence), 35.0 kD (experimental) [Watanabe12 ]

Molecular Weight of Multimer: 275.0 kD (experimental) [Watanabe12]

Unification Links: Entrez-gene:1042610 , Protein Model Portal:Q88NF4 , String:160488.PP_1257 , UniProt:Q88NF4

Relationship Links: InterPro:IN-FAMILY:IPR002220 , InterPro:IN-FAMILY:IPR013785 , Panther:IN-FAMILY:PTHR12128 , Pfam:IN-FAMILY:PF00701 , Prints:IN-FAMILY:PR00146

Gene-Reaction Schematic: ?

Created 29-Apr-2013 by Fulcher CA , SRI International
Revised 29-Apr-2013 by Fulcher CA , SRI International

Enzymatic reaction of: Δ1-pyrroline-4-hydroxy-2-carboxylate deaminase

Synonyms: 1-pyrroline-4-hydroxy-2-carboxylate deaminase

EC Number:

1-pyrroline-4-hydroxy-2-carboxylate + H+ + H2O <=> ammonium + 2,5-dioxopentanoate

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is favored in the direction shown.

In Pathways: trans-4-hydroxy-L-proline degradation II

This enzyme was assayed spectrophotometrically in a coupled assay using α-ketoglutaric semialdehyde dehydrogenase and monitoring the increase in absorbance of the NADPH produced [Watanabe12].

In earlier work the enzyme was found to be inducible when the the organism was grown on hydroxyproline as sole carbon and nitrogen source. The enzyme was shown to be highly substrate-specific. A reverse reaction could not be detected. The reaction product was characterized as 2,5-dioxovalerate [Singh65].

Inhibitors (Competitive): pyruvate (Kic = 492µM) [Watanabe12] , 2-dehydro-3-deoxy-L-arabinonate (Kic = 592µM) [Watanabe12]

Inhibitors (Unknown Mechanism): Hg2+ [Singh65a] , copper sulfate [Singh65a] , Ag+ [Singh65a] , p-mercuribenzoate [Singh65a]

Kinetic Parameters:

Km (μM)
kcat (sec-1)
kcat/Km (sec-1 μM-1)

T(opt): 37 °C [Singh65a]

pH(opt): 6.5-7.5 [Singh65a]


Singh65: Singh RM, Adams E (1965). "Isolation and identification of 2,5-dioxovalerate, an intermediate in the bacterial oxidation of hydroxyproline." J Biol Chem 240(11);4352-6. PMID: 5845839

Singh65a: Singh RM, Adams E (1965). "Enzymatic deamination of delta-1-pyrroline-4-hydroxy-2-carboxylate to 2,5-dioxovalerate (alpha-ketoglutaric semialdehyde)." J Biol Chem 240(11);4344-51. PMID: 5845838

Watanabe12: Watanabe S, Morimoto D, Fukumori F, Shinomiya H, Nishiwaki H, Kawano-Kawada M, Sasai Y, Tozawa Y, Watanabe Y (2012). "Identification and characterization of D-hydroxyproline dehydrogenase and Delta1-pyrroline-4-hydroxy-2-carboxylate deaminase involved in novel L-hydroxyproline metabolism of bacteria: metabolic convergent evolution." J Biol Chem 287(39);32674-88. PMID: 22833679

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 18.5 on Thu Feb 26, 2015, BIOCYC13A.