title: Prohormone-substrate peptide sequence recognition by peptidylglycine α-amidating monooxygenase and its reflection in increased glycolate inhibitor potency.
abstract: The interactions of nineteen peptide substrates and fifteen analogous peptidomimetic glycolate inhibitors with human peptidylglycine α-amidating monooxygenase (PAM) have been investigated. The substrates and inhibitors are the prohormones of calcitonin and oxytocin and their analogues. PAM both secreted into the medium by and extracted from DMS53 small lung carcinoma cells has been studied. The results show that recognition of the prooxytocin and procalcitonin peptide sequences by the enzyme extends more than four and five amino acid residues, respectively, from their C-termini. This substrate sequence recognition is mirrored by increased inhibitor potency with increased peptide length in the glycolate peptidomimetics. Substitution of the C-terminal penultimate glycine and proline residues of prooxytocin and procalcitonin and their analogues with phenylalanine increases the enzyme binding affinity. However, this changes the binding mode from one that depends on peptide sequence recognition to another primarily determined by the phenylalanine moiety, for both the substrates and analogous glycolate inhibitors.
authors.affiliation: ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia.
authors.forename: Kelly M
authors.initials: KM
authors.lastname: Morris
authors.forename: Feihua
authors.initials: F
authors.lastname: Cao
authors.forename: Hideki
authors.initials: H
authors.lastname: Onagi
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Altamore
authors.forename: Allan B
authors.initials: AB
authors.lastname: Gamble
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Easton
mesh_terms: D000595:Amino Acid Sequence; D002116:Calcitonin / Q000737:chemistry / Q000378:metabolism; D015740:Calcitonin Gene-Related Peptide; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism*; D006016:Glycolates / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D006899:Mixed Function Oxygenases / Q000737:chemistry / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000737:chemistry / Q000378:metabolism*; D010121:Oxytocin / Q000737:chemistry / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D057786:Peptidomimetics; D011485:Protein Binding; D011498:Protein Precursors / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: C000606589:CALCA protein, human; D004791:Enzyme Inhibitors; D006016:Glycolates; D009097:Multienzyme Complexes; D010455:Peptides; D057786:Peptidomimetics; D011498:Protein Precursors; C031149:glycolic acid; D010121:Oxytocin; D002116:Calcitonin; D006899:Mixed Function Oxygenases; C035189:peptidylglycine monooxygenase; D015740:Calcitonin Gene-Related Peptide