Lipase from Chromobacterium viscosum: biochemical characterization indicating homology to the lipase from Pseudomonas glumae

Previous purification of a commercial lipolytic preparation from Chromobacterium viscosum using gel filtration chromatography yielded two enzymatically active fractions, named lipases A and B. Characterization of these fractions by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that Lipase A consisted of a high molecular weight aggregate of Lipase protein with lipopolysaccharides. This complex could be dissociated by treatment with EDTA-Tris buffer containing the non-ionic detergent n-octyl-beta-D-glucopyranoside and subsequent isoelectric focusing in an Agarose gel containing the same detergent. Both lipases A and B revealed a major peak corresponding to an isoelectric point of 7.1. SDS-PAGE analysis of lipases A and B after purification by gel filtration or by IEF revealed one major protein band of M(r) of 33 K. Determination of N-terminal amino acid sequences confirmed that both fractions A and B contained the same Lipase protein. Furthermore, the N-terminal amino acid sequence of the C. viscosum Lipase was identical to the one of Pseudomonas glumae Lipase.