title: Streptomyces griseus aminopeptidase is a calcium-activated zinc metalloprotein. Purification and properties of the enzyme.
abstract: A heat-stable aminopeptidase with an N-terminal Ala-Pro-Asp-Ile-Pro-Leu sequence has been purified from Streptomyces griseus by heat treatment followed by gel-exclusion and anion-exchange chromatographic procedures. The enzyme is a monomeric zinc metalloenzyme showing an apparent molecular mass of 33 kDa by sodium dodecyl sulfate/polyacrylamide gel electrophoresis and 21 kDa by gel filtration on Superose 12. Calcium ions bind to the enzyme, pKCa 4.5, and activate it about sixfold when the substrate is leucine-4-nitroanilide (0.4 mM in 50 mM Tris/HCl pH 8.0, 25 degrees C). Binding of Ca2+ also contributes to the thermal stability of the protein. This aminopeptidase may be useful for two-stage assays of bacterial and mammalian metalloendopeptidases; it may also serve in studies of proteolytic enzyme activation by calcium ions.
authors.affiliation: Sackler Institute of Molecular Medicine, Sackler Faculty of Medicine, Tel Aviv University, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Spungin
authors.forename: S
authors.initials: S
authors.lastname: Blumberg
mesh_terms: D000595:Amino Acid Sequence; D000626:Aminopeptidases / Q000302:isolation & purification* / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology*; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004355:Drug Stability; D004492:Edetic Acid / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D006358:Hot Temperature; D008667:Metalloproteins; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010618:Phenanthrolines / Q000494:pharmacology; D013305:Streptomyces griseus / Q000201:enzymology*; D015032:Zinc / Q000032:analysis*
chemical_list: D008667:Metalloproteins; D010618:Phenanthrolines; D004533:Egtazic Acid; D004492:Edetic Acid; D000626:Aminopeptidases; D015032:Zinc; D002118:Calcium; C025205:1,10-phenanthroline