Peptidyl-glycine alpha-amidating monooxygenase is an enzyme that is required for the biosynthesis of many signaling peptides. This transformation is achieved by conversion of a prohormone to the corresponding amide (C(O)NH2). This enzyme is the only known pathway for generating peptide amides, which renders the peptide more hydrophilic.[1] In humans, PAM is encoded by the PAMgene.[2][3]
Function
This gene encodes a multifunctional protein. It has two enzymatically active domains with catalytic activities - peptidylglycine alpha-hydroxylating monooxygenase (PHM) and peptidyl-alpha-hydroxyglycine alpha-amidating lyase (PAL). These catalytic domains work sequentially to catalyze neuroendocrinepeptides to active alpha-amidated products. Multiple alternatively spliced transcript variants encoding different isoforms have been described for this gene, but some of their full-length sequences are not yet known.[3]
The PHM subunit effects hydroxylation of an O-terminal glycine residue:
Involving hydroxylation of a hydrocarbon by O2, this process relies on a copper cofactor. Dopamine beta-hydroxylase, also a copper-containing enzyme, effects a similar transformation.
The PAL subunit then completes the conversion, by catalyzing elimination from the hydroxylated glycine:
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