title: Inhibition of Streptomyces griseus aminopeptidase and effects of calcium ions on catalysis and binding--comparisons with the homologous enzyme Aeromonas proteolytica aminopeptidase.
abstract: Streptomyces griseus aminopeptidase is a zinc metalloenzyme containing 2 mol zinc/mol protein, similar to the homologous enzyme Aeromonas proteolytica aminopeptidase. In addition, a unique Ca2+-binding site has been identified in the Streptomyces enzyme, which is absent in the Aeromonas enzyme. Binding of Ca2+ enhances stability of the Streptomyces enzyme and modulates its activity and affinity towards substrates and inhibitors in a structure-dependent manner. Among the three hydrophobic 4-nitroanilides of alanine, valine and leucine, the latter displays the largest overall activation (increase in k(cat)/Km). Large enhancements in affinity (1/Ki) upon Ca2+ binding have been observed for inhibitors with flexible (leucine-like) residues at their N-termini and smaller enhancements for inhibitors with rigid (phenylalanine-like) residues.
authors.affiliation: Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine, Sackler Faculty of Medicine, Tel Aviv University, Israel.
authors.forename: G
authors.initials: G
authors.lastname: Papir
authors.forename: A
authors.initials: A
authors.lastname: Spungin-Bialik
authors.forename: D
authors.initials: D
authors.lastname: Ben-Meir
authors.forename: E
authors.initials: E
authors.lastname: Fudim
authors.forename: R
authors.initials: R
authors.lastname: Gilboa
authors.forename: H M
authors.initials: HM
authors.lastname: Greenblatt
authors.forename: G
authors.initials: G
authors.lastname: Shoham
authors.forename: U
authors.initials: U
authors.lastname: Lessel
authors.forename: D
authors.initials: D
authors.lastname: Schomburg
authors.forename: R
authors.initials: R
authors.lastname: Ashkenazi
authors.forename: S
authors.initials: S
authors.lastname: Blumberg
mesh_terms: D000333:Aeromonas / Q000201:enzymology*; D000626:Aminopeptidases / Q000737:chemistry*; D000813:Anilides / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000737:chemistry; D001665:Binding Sites / Q000502:physiology; D002118:Calcium / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability / Q000187:drug effects; D007700:Kinetics; D007930:Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D008667:Metalloproteins / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D010455:Peptides; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D013305:Streptomyces griseus / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D000813:Anilides; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D008667:Metalloproteins; D010455:Peptides; C016977:amastatin; D000626:Aminopeptidases; C038222:bacterial leucyl aminopeptidase; D007930:Leucine; C012211:ubenimex; D002118:Calcium