title: Characterization of cell-bound papain-soluble beta-lactamases in BRO-1 and BRO-2 producing strains of Moraxella (Branhamella) catarrhalis and Moraxella nonliquefaciens.
abstract: In Moraxella (Branhamella) catarrhalis and Moraxella nonliquefaciens strains isolated from clinical specimens in the south of Sweden two variants of beta-lactamase were distinguished by isoelectric focusing (IEF). The BRO-1 (Ravasio type) enzyme was the most common in Branhamella catarrhalis, constituting about 90% of the beta-lactamase found in this species, while the BRO-2 enzyme (1908 type) was as common as BRO-1 in Moraxella nonliquefaciens. The determinants mediating the production of BRO-1 and BRO-2 were both transferable by conjugation. Cell-bound beta-lactamase from reference strains producing BRO-1 and BRO-2 could be solubilized by papain digestion. The isoelectric point of the solubilized enzymes differed distinctly between BRO-1 (pI 6.5) and BRO-2 (pI 6.9). The molecular species of BRO-1 and BRO-2 released by papain digestion were purified by affinity chromatography with phenylboronic acid agarose gel. They had identical molecular weights of approximately 28,000. Their kinetic constants were indistinguishable for a number of substrates and beta-lactamase inhibitors.
authors.affiliation: Department of Medical Microbiology, University of Lund, Sweden.
authors.forename: I
authors.initials: I
authors.lastname: Eliasson
authors.forename: C
authors.initials: C
authors.lastname: Kamme
authors.forename: M
authors.initials: M
authors.lastname: Vang
authors.forename: S G
authors.initials: SG
authors.lastname: Waley
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism; D002846:Chromatography, Affinity; D003227:Conjugation, Genetic; D004587:Electrophoresis, Agar Gel; D007526:Isoelectric Point; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D008970:Molecular Weight; D009016:Moraxella / Q000201:enzymology*; D001936:Moraxella catarrhalis / Q000201:enzymology*; D010206:Papain / Q000378:metabolism; D013548:Sweden; D001618:beta-Lactamases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D010206:Papain; D001618:beta-Lactamases