Purification and characterization of an extracellular proline iminopeptidase from Arthrobacter nicotianae 9458 |
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Authors: | Emanuele Smacchi Marco Gobbetti Rosalba Lanciotti Patrick F Fox |
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Institution: | Istituto di Industrie Agrarie (Microbiologia), Facoltà di Agraria, Università degli Studi di Perugia, Italy. |
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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. |
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Keywords: | Peptidase Proline iminopeptidase Smear surface-ripened cheese Arthrobacter |
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