The role of ascorbate in the biosynthesis of neuroendocrine peptides.

The biosynthesis of all alpha-amidated peptides requires the participation of peptidylglycine alpha-amidating monooxygenase (PAM), a bifunctional enzyme dependent on molecular oxygen, ascorbate, and copper. In the AtT-20 corticotrope cell line, reduced concentrations of PAM and ascorbate can make alpha-amidation the rate-limiting step in the production of bioactive product peptide. Production of various peptides thought to play autocrine and paracrine roles may be affected by ascorbate availability.