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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:dateCreated |
1996-12-31
|
| pubmed:abstractText |
An aminopeptidase with a very broad substrate specificity was purified to homogeneity from Lactobacillus helveticus SBT 2171 by FPLC. The enzyme was purified 144-fold from a cell-free extract with a yield of 16%. The purified enzyme appeared as a single band on an SDS-PAGE gel. It had a molecular mass of 95 kDa and an isoelectric point of 4.9. The enzyme hydrolysed a large range of naphthylamide- and nitroanilide-substituted amino acids, as well as several di-, tri- and oligopeptides. It also exhibited significant proline-iminopeptidase-like activity, since it hydrolysed several proline-containing peptides. Prolyl-p-nitroanilide was hydrolysed with a low affinity (Michaelis-Menten constant 0.6 mM) and a Vmax of 2.5 mumol min-1 (mg protein)-1 while lysyl-p-nitroanilide was hydrolysed with a high affinity [Km 0.003 mM; Vmax 37.5 mumol min-1 (mg protein)-1]. The aminopeptidase activity, which was optimal between pH 6.0 and 8.0 and at 50 degrees C, was very stable at 30 degrees C for more than 7 d. The activity lost by treatment with the thiol-blocking reagents could be restored with beta-mercaptoethanol, while Co2+ and Mn2+ restored the activity of the EDTA-treated enzyme. Immunological experiments with antibodies raised against the aminopeptidases from Lactococcus lactis and Lb. helveticus clearly showed that both aminopeptidases are at least immunologically different from each other.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Apr
|
| pubmed:issn |
1350-0872
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
142 ( Pt 4)
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
799-808
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading |
pubmed-meshheading:8936307-Amino Acid Sequence,
pubmed-meshheading:8936307-Aminopeptidases,
pubmed-meshheading:8936307-Dairy Products,
pubmed-meshheading:8936307-Enzyme Stability,
pubmed-meshheading:8936307-Hydrogen-Ion Concentration,
pubmed-meshheading:8936307-Immunochemistry,
pubmed-meshheading:8936307-Isoelectric Point,
pubmed-meshheading:8936307-Kinetics,
pubmed-meshheading:8936307-Lactobacillus,
pubmed-meshheading:8936307-Molecular Sequence Data,
pubmed-meshheading:8936307-Molecular Weight,
pubmed-meshheading:8936307-Oligopeptides,
pubmed-meshheading:8936307-Substrate Specificity,
pubmed-meshheading:8936307-Temperature
|
| pubmed:year |
1996
|
| pubmed:articleTitle |
A new, broad-substrate-specificity aminopeptidase from the dairy organism Lactobacillus helveticus SBT 2171.
|
| pubmed:affiliation |
Snow Brand European Research Laboratories, Groningen, Netherlands.
|
| pubmed:publicationType |
Journal Article
|