Phosphopantothenate—cysteine ligase
Template:Short description Template:Infobox enzyme In enzymology, a phosphopantothenate—cysteine ligase also known as phosphopantothenoylcysteine synthetase (PPCS) is an enzyme (Template:EnzExplorer) 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 NMP + diphosphate + N-[(R)-4'-phosphopantothenoyl]-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).[1]
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
Template:Infobox gene Phosphopantothenoylcysteine synthetase in humans is encoded by the PPCS gene.[2]
Protein structure
As of late 2007, 5 structures have been solved for this class of enzymes, with PDB accession codes Template:PDB link, Template:PDB link, Template:PDB link, Template:PDB link, and Template:PDB link.
References
Further reading
External links
- PDBe-KB provides an overview of all the structure information available in the PDB for Human Phosphopantothenate—cysteine ligase
Template:Ligases CO CS and CN Template:Enzymes Template:Portal bar