Alginate lyases from alginate-degrading Vibrio splendidus 12B01 are endolytic.

ABSTRACT: Alginate lyases are enzymes that degrade alginate through ?-elimination of the glycosidic bond into smaller oligomers. We investigated the alginate lyases from Vibrio splendidus 12B01, a marine bacterioplankton species that can grow on alginate as its sole carbon source. We identified, purified, and characterized four polysaccharide lyase family 7 alginates lyases, AlyA, AlyB, AlyD, and AlyE, from V. splendidus 12B01. The four lyases were found to have optimal activity between pH 7.5 and 8.5 and at 20 to 25°C, consistent with their use in a marine environment. AlyA, AlyB, AlyD, and AlyE were found to exhibit a turnover number (kcat) for alginate of 0.60 ± 0.02 s(-1), 3.7 ± 0.3 s(-1), 4.5 ± 0.5 s(-1), and 7.1 ± 0.2 s(-1), respectively. The Km values of AlyA, AlyB, AlyD, and AlyE toward alginate were 36 ± 7 ?M, 22 ± 5 ?M, 60 ± 2 ?M, and 123 ± 6 ?M, respectively. AlyA and AlyB were found principally to cleave the ?-1,4 bonds between ?-d-mannuronate and ?-l-guluronate and subunits; AlyD and AlyE were found to principally cleave the ?-1,4 bonds involving ?-l-guluronate subunits. The four alginate lyases degrade alginate into longer chains of oligomers.

SUBMITTER: Badur AH 

PROVIDER: S-EPMC4325137 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature