Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023241 (Legionella)
 6,990 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The enzyme-linked immunosorbent assay (ELISA) has been evaluated for the detection of antibodies against Legionella pneumophila. Three-grade antigens were prepared from Legionella pneumophila serogroup I. Crude antigen was made by enzyme digestion, sonication and centrifugation and then became half pure by ammonium sulfate precipitation. It was purified to form 60-kDa protein antigen by size-exclusion chromatography on a Sephacryl S400 column and ion-exchanged chromatography on a DEAE-5PW column. 60-kDa protein antigen was the most sensitive of the three antigens, but more cross reactive to K. pneumoniae type II than the other two antigens. It is suggested that crossreaction occurs on the grounds whether 60-kDa protein is antigen common to L. pneumophila serogroup I and K. pneumoniae type II or antigens of such two bacteria co-exist on 60-kDa protein.
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PMID:[Enzyme-linked immunosorbent assay (ELISA) for Legionella pneumophila using 60-kDa protein antigen]. 228 87

An extracellular proteolytic enzyme of Legionella pneumophila was purified by sequential batch separation with DEAE-cellulose, hydrophobic interaction chromatography with octyl-Sepharose, and ion-exchange chromatography with DEAE-Bio-Gel A (Bio-Rad Laboratories, Richmond, Calif.). The resulting protease preparation was determined to be homogeneous by polyacrylamide gel electrophoresis in the presence and absence of sodium dodecyl sulfate. Although free of contaminating proteins, the purified protease separated into two antigenically indistinguishable proteins both of which possessed proteolytic activity. The apparent masses of the proteins were 38 and 40 kilodaltons (kDa) as determined by polyacrylamide gel electrophoresis in sodium dodecyl sulfate, whereas gel filtration chromatography revealed a single mass of 34 kDa. Immunoblot analysis indicated that the 38-kDa protein probably originated from the 40-kDa protein during purification. The isoelectric points of the two protease species were 4.20 and 4.42. Enzyme activity, which was optimum between pH 5.5 and 7.5, was inhibited by various metal chelators; however, no effect was observed after treatment with phenylmethylsulfonyl fluoride, chymostatin, trypsin inhibitor, or dithiothreitol. Enzyme activity inhibited by metal chelators was restored upon the addition of various metal ions, including Zn2+, Fe2+, Mn2+, Cu2+, and Fe3+, but was not restored by Mg2+ or Ca2+. Atomic absorption analysis of the purified protease revealed a single gram-atom of zinc per mole of enzyme. Our findings indicate that the L. pneumophila protease resembles neutral zinc-containing metalloproteases similar to those found in other bacterial species.
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PMID:Purification and characterization of an extracellular protease of Legionella pneumophila. 351 31