phosphopantothenate-cysteine ligase (phosphopantothenoylcysteine synthetase, PPC synthetase, PPCS, COAB)

Function

• catalyzes the first step in the biosynthesis of coenzyme A from vitamin B5
  • conjugation of cysteine to 4'-phosphopantothenate to form 4-phosphopantothenoylcysteine
• mammalian enzyme has a preference for ATP over CTP, in contrast to the E. coli ortholog

CTP + (R)-4'-phosphopantothenate + L-cysteine
              <-->
CMP + PPi + N-((R)-4'-phosphopantothenoyl)-L-cysteine

Structure

homodimer

More general terms

• ligase or synthetase

Database

• UniProt: http://www.uniprot.org/uniprot/Q9HAB8.html