Phosphopantothenoylcysteine Synthetase

In enzymology, a phosphopantothenate-cysteine ligase also known as phosphopantothenoylcysteine synthetase (PPCS) is an enzyme 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--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).

Read more about Phosphopantothenoylcysteine Synthetase:  Nomenclature, Gene, Protein Structure