Purification and Characterization of κ-Carrageenase from a Marine Bacterium, <i>Vibrio</i> sp. CA-1004

Abstract

A κ-carrageenase-producing bacterium strain CA-1004 was isolated from the surface of a marine alga and identified to Vibrio sp. The strain produced a large amount of extracellular κ-carrageenase. A κ-carrageenase was purified 58-fold from cell-free culture fluid by ammonium sulfate precipitation and successive chromatographies. By SDS-PAGE the enzyme was ascertained to be homogeneous and had a molecular mass of 35 kDa. The enzyme exhibited maximal activity at pH 8.0 and 40°C. The pI and Km of the enzyme were 9.2 and 3.3mg/ml, respectively. The enzyme activity was completely inhibited by Zn2+, Pb2+, Hg2+, and N-bromosuccinimide. The enzyme hydrolyzed κ-carrageenan and larger neocarraoligosaccharide sulfates than neocarrabiose sulfate to produce mainly neocarra-biose and-tetraose sulfates but did not act on neocarrabiose sulfate, p-nitrophenyl-α- and β-D-galactopyranosides, λ- and ι-carrageenans, agar, and porphyran.