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Purification and characterization of a lysine-p-nitroanilide hydrolase, a broad specificity aminopeptidase, from the cytoplasm of Lactococcus lactis subsp. cremoris AM2

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dc.contributor.author McDonnell, Maeve
dc.contributor.author Bouchier, Paul
dc.contributor.author Fitzgerald, Richard J.
dc.contributor.author O'Cuinn, Gerard
dc.date.accessioned 2013-04-08T15:45:46Z
dc.date.available 2013-04-08T15:45:46Z
dc.date.issued 1999
dc.identifier.uri http://hdl.handle.net/10344/3025
dc.description peer-reviewed en_US
dc.description.abstract Summary. A hydrolase activity that cleaves lysyl-p-nitroanilide (Lys-pNA) has been purified from the cytoplasm of Lactococcus lactis subsp. cremoris AM2 by chromatography on DE52, DEAE Affi-Gel Blue Gel, Hydroxyapatite Bio-Gel HTP and Phenyl Sepharose. The purified aminopeptidase was found to have a native Mr of 50000-55000 by gel filtration chromatography and by FPLC gel filtration on Superose 12 and to be composed of a single polypeptide chain following SDS-PAGE. Enzyme activity was almost completely inhibited by EDTA, amastatin, puromycin and bestatin, while the sulphydryl-reactive agents p-chloromercuribenzoate and iodoacetamide were inhibitory. The enzyme was found to be very unstable during the puriification procedures at 4 °C and its stability was greatly improved when 10 ml glycerol/l and 2 mm-dithiothreitol were included in the puri®cation buffers. The puriified enzyme was found to hydrolyse a wide range of dipeptides, tripeptides and longer peptides provided that proline was not present in the penultimate position from the N-terminus or that a pyroglutamyl residue was not present at the N-terminus. While neither Asp-pNA nor Pro-pNA was hydrolysed by the purified enzyme, the release of N-terminal acidic residues from peptides was observed in addition to the release of N-terminal proline from Pro-Leu-Gly-NH2, Pro-Leu- Gly-Gly and Pro-His-Pro-Phe-His-Leu-Phe-Val-Tyr. This ability of Lys-pNA hydrolase to release N-terminal proline residues was employed in concert with a puriified aminopeptidase P preparation to release alternate N-terminal amino acids from Tyr-Pro-Phe-Pro-Gly. The complementary action of these enzymes represents an alternative mechanism to that of post-proline dipeptidyl aminopeptidase for metabolism of proline-containing peptides. en_US
dc.language.iso eng en_US
dc.publisher Cambridge University Press en_US
dc.relation.ispartofseries Journal of Dairy Research;66, pp. 257-270
dc.relation.uri http://journals.cambridge.org/action/displayBackIssues?jid=dar
dc.rights Material on these pages is copyright Cambridge University Press or reproduced with permission from other copyright owners. It may be downloaded and printed for personal reference, but not otherwise copied, altered in any way or transmitted to others (unless explicitly stated otherwise) without the written permission of Cambridge University Press. Hypertext links to other Web locations are for the convenience of users and do not constitute any endorsement or authorisation by Cambridge University Press. en_US
dc.subject lactoccus lactis en_US
dc.subject purification procedures en_US
dc.subject peptides en_US
dc.title Purification and characterization of a lysine-p-nitroanilide hydrolase, a broad specificity aminopeptidase, from the cytoplasm of Lactococcus lactis subsp. cremoris AM2 en_US
dc.type info:eu-repo/semantics/article en_US
dc.type.supercollection all_ul_research en_US
dc.type.supercollection ul_published_reviewed en_US
dc.contributor.sponsor FORBAIRT en_US
dc.contributor.sponsor Dairy Levy Fund en_US
dc.contributor.sponsor National Dairy Products Research Centre en_US
dc.rights.accessrights info:eu-repo/semantics/closedAccess en_US


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