title: Glutathione, S-substituted glutathiones, and leukotriene C4 as substrates for peptidylglycine alpha-amidating monooxygenase.
abstract: The C-terminal alpha-amide moiety of most peptide hormones arises by the posttranslational cleavage of a glycine-extended precursor in a reaction catalyzed by bifunctional peptidylglycine alpha-amidating monooxygenase (PAM). Glutathione and the S-alkylated glutathiones have a C-terminal glycine and are, thus, potential substrates for PAM. The addition of PAM to glutathione, a series of S-alkylated glutathiones, and leukotriene C(4) results in the consumption of O(2) and the production of the corresponding amidated peptide and glyoxylate. This reaction proceeds in two steps with the intermediate formation of a C-terminal alpha-hydroxyglycine-extended peptide. Amidated glutathione (gammaGlu-Cys-amide) is a relatively poor substrate for glutathione S-transferase with a V/K value that is 1.3% of that for glutathione. Peptide substrates containing a penultimate hydrophobic or sulfur-containing amino acid exhibit the highest (V/K)(app) values for PAM-catalyzed amidation. The S-alkylated glutathiones incorporate both features in the penultimate position with S-decylglutathione having the highest (V/K)(app) of the substrates described in this report.
authors.affiliation: Department of Chemistry, University of South Florida, Tampa, FL 33620, USA.
authors.forename: Laura Aaron
authors.initials: LA
authors.lastname: Miller
authors.forename: Laura E
authors.initials: LE
authors.lastname: Baumgart
authors.forename: Geoffrey H
authors.initials: GH
authors.lastname: Chew
authors.forename: Mitchell A
authors.initials: MA
authors.lastname: deLong
authors.forename: Lamar C
authors.initials: LC
authors.lastname: Galloway
authors.forename: Kyung Woon
authors.initials: KW
authors.lastname: Jung
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Merkler
authors.forename: Advait S
authors.initials: AS
authors.lastname: Nagle
authors.forename: Derek D
authors.initials: DD
authors.lastname: Poore
authors.forename: Cheol Hwan
authors.initials: CH
authors.lastname: Yoon
authors.forename: David J
authors.initials: DJ
authors.lastname: Merkler
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D004305:Dose-Response Relationship, Drug; D005978:Glutathione / Q000737:chemistry*; D005982:Glutathione Transferase / Q000378:metabolism; D006736:Horses; D006868:Hydrolysis; D007700:Kinetics; D017997:Leukotriene C4 / Q000737:chemistry*; D013058:Mass Spectrometry; D006899:Mixed Function Oxygenases / Q000737:chemistry*; D008956:Models, Chemical; D009097:Multienzyme Complexes / Q000737:chemistry*; D010100:Oxygen / Q000378:metabolism; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D013997:Time Factors
chemical_list: D000596:Amino Acids; D009097:Multienzyme Complexes; D010455:Peptides; D017997:Leukotriene C4; D006899:Mixed Function Oxygenases; C035189:peptidylglycine monooxygenase; D005982:Glutathione Transferase; D005978:Glutathione; D010100:Oxygen