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In enzymology, a phosphopantothenate—cysteine ligase also known as phosphopantothenoylcysteine synthetase (PPCS) is an enzyme (EC 6.3.2.5) that catalyzes the chemical reaction which constitutes the second of five steps involved in the conversion of pantothenate to Coenzyme A. The reaction is:

NTP + (R)-4'-phosphopantothenate + L-cysteine ${\displaystyle \rightleftharpoons }$ NMP + diphosphate + N--L-cysteine

The nucleoside triphosphate (NTP) involved in the reaction varies from species to species. Phosphopantothenate—cysteine ligase from the bacterium Escherichia coli uses cytidine triphosphate (CTP) as an energy donor, whilst the human isoform uses adenosine triphosphate (ATP).

Nomenclature

This enzyme belongs to the family of ligases, specifically those forming carbon-nitrogen bonds as acid-D-amino-acid ligases (peptide syntheses). The systematic name of this enzyme class is (R)-4'-phosphopantothenate:L-cysteine ligase. This enzyme is also called phosphopantothenoylcysteine synthetase.

Gene

PPCS
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 1P9O
Identifiers
Aliases	PPCS, Phosphopantothenate—cysteine ligase, phosphopantothenoylcysteine synthetase, CMD2C
External IDs	OMIM: 609853; MGI: 1915237; HomoloGene: 6173; GeneCards: PPCS; OMA:PPCS - orthologs
Gene location (Human) Chr. Chromosome 1 (human) Band 1p34.2 Start 42,456,117 bp End 42,473,385 bp
Gene location (Mouse) Chr. Chromosome 4 (mouse) Band 4|4 D2.1 Start 119,275,727 bp End 119,279,617 bp
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in right adrenal cortex body of pancreas Achilles tendon rectum mucosa of transverse colon monocyte left adrenal gland left adrenal cortex body of stomach gallbladder Top expressed in right kidney transitional epithelium of urinary bladder proximal tubule lumbar spinal ganglion yolk sac adrenal gland left lobe of liver human kidney epithelium of small intestine duodenum More reference expression data BioGPS n/a
Gene ontology Molecular function phosphopantothenate--cysteine ligase activity ligase activity Cellular component cytosol Biological process coenzyme A biosynthetic process Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 79717 106564 Ensembl ENSG00000127125 ENSMUSG00000028636 UniProt Q9HAB8 Q8VDG5 RefSeq (mRNA) NM_001077447 NM_001287506 NM_001287507 NM_001287508 NM_001287509 NM_001287510 NM_001287511 NM_024664 NM_026494 NM_001355214 RefSeq (protein) NP_001070915 NP_001274435 NP_001274436 NP_001274437 NP_001274438 NP_001274439 NP_001274440 NP_078940 NP_080770 NP_001342143 Location (UCSC) Chr 1: 42.46 – 42.47 Mb Chr 4: 119.28 – 119.28 Mb PubMed search
Wikidata
View/Edit Human View/Edit Mouse

Phosphopantothenoylcysteine synthetase in humans is encoded by the PPCS gene.

Protein structure

As of late 2007, 5 structures have been solved for this class of enzymes, with PDB accession codes 1P9O, 1U7U, 1U7W, 1U7Z, and 1U80.

References

1. Manoj N, Strauss E, Begley TP, Ealick SE (Aug 2003). "Structure of human phosphopantothenoylcysteine synthetase at 2.3 A resolution". Structure. 11 (8): 927–936. doi:10.1016/S0969-2126(03)00146-1. PMID 12906824.
2. ^ GRCh38: Ensembl release 89: ENSG00000127125 – Ensembl, May 2017
3. ^ GRCm38: Ensembl release 89: ENSMUSG00000028636 – Ensembl, May 2017
4. "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
5. "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
6. "Entrez Gene: Phosphopantothenoylcysteine synthetase".

Further reading

• Brown GM (1959). "The metabolism of pantothenic acid". J. Biol. Chem. 234 (2): 370–8. doi:10.1016/S0021-9258(18)70307-4. PMID 13630913.
• Strauss E, Kinsland C, Ge Y, McLafferty FW, Begley TP (2001). "Phosphopantothenoylcysteine synthetase from Escherichia coli Identification and characterization of the last unidentified coenzyme A biosynthetic enzyme in bacteria". J. Biol. Chem. 276 (17): 13513–6. doi:10.1074/jbc.C100033200. PMID 11278255.
• Kupke T (2002). "Molecular characterization of the 4'-phosphopantothenoylcysteine synthetase domain of bacterial dfp flavoproteins". J. Biol. Chem. 277 (39): 36137–45. doi:10.1074/jbc.M206188200. PMID 12140293.

External links

• PDBe-KB provides an overview of all the structure information available in the PDB for Human Phosphopantothenate—cysteine ligase

• Biology

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• Genes on human chromosome 1
• EC 6.3.2
• Enzymes of known structure
• Ligase stubs