Characterization of a Novel Alginate Lyase from Flavobacterium multivolum K-11

Abstract

An alginate lyase was purified from an extracellular enzyme (commercial preparation) of Flavobacterium multivolum K-11 by successive column chromatographies, such as cation exchange, chromatofocusing, and gel filtration. The purified enzyme migrated as a single band on SDS-PAGE and analytical isoelectric focusing. The molecular weight of the enzyme was 32,000 by SDS-PAGE and 33,000 by HPLC gel filtration chromatography, and the pI of the enzyme was 8.2 on isoelectric focusing. The enzyme exhibited maximum activity at pH 7.5 and 40°C, and was stable between pH 6.0 and 9.0, and at temperatures up to 20°C. The enzyme activity was remarkably inhibited by chemical compounds such as SDS, MIA, TNBS, and N-bromosuccinimide, while EDTA and PCMB had no effect on the enzyme activity. The enzyme decomposed both the G-block (guluronic acid content; 89%) and the M-block (mannuronic content; 92%) at nearly equal rates, and produced several kinds of unsaturated oligomers. Because such activity of alginate lyase has not been reported, we believe that this is a novel alginate lyase.