title: Purification and characterization of an extracellular proline iminopeptidase from Arthrobacter nicotianae 9458.
abstract: An extracellular proline iminopeptidase, with a molecular mass of about 53 kDa, was purified from Arthrobacter nicotianae 9458 and characterized. The enzyme had temperature and pH optima of 37 degrees C and 8.0, respectively, was completely inactivated by heating for 1 min at 80 degrees C and showed highest activity on Pro-pNA. The proline iminopeptidase was characterized by activity at low temperature, NaCl concentrations up to 7.5% and by high sensitivity to pH values 6.0, serine enzyme inhibitor PMSF and divalent cations, Fe2+, Sn2+, Cu2+, Zn2+, Hg2+, Co2+ and Ni2+. The extracellular proline iminopeptidase from A. nicotianae 9458 was able to hydrolyze proline-containing peptides at the pH, temperature and NaCl concentration typical of the surface of smear-ripened cheese and may contribute to proteolysis of these cheeses during ripening.
authors.affiliation: Istituto di Industrie Agrarie (Microbiologia), Facoltà di Agraria, Università degli Studi di Perugia, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Smacchi
authors.forename: M
authors.initials: M
authors.lastname: Gobbetti
authors.forename: R
authors.initials: R
authors.lastname: Lanciotti
authors.forename: P F
authors.initials: PF
authors.lastname: Fox
mesh_terms: D000626:Aminopeptidases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D001173:Arthrobacter / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D002611:Cheese / Q000382:microbiology; D003080:Cold Temperature; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D012965:Sodium Chloride
chemical_list: D001426:Bacterial Proteins; D012965:Sodium Chloride; D000626:Aminopeptidases; C022450:prolyl aminopeptidase