Effect of Enzyme Preparation from the Marine Mollusk Littorina kurila on Fucoidan from the Brown Alga Fucus distichus

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M. I. Bilan¹, M. I. Kusaykin², A. A. Grachev¹, E. A. Tsvetkova¹, T. N. Zvyagintseva², N. E. Nifantiev¹, and A. I. Usov^1*

¹Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninskii pr. 47, 119991 Moscow, Russia; fax: (7-095) 135-5328; E-mail: usov@ioc.ac.ru

²Pacific Institute of Bioorganic Chemistry, Far-Eastern Branch, Russian Academy of Sciences, pr. 100-letiya Vladivostoka 159, 690022 Vladivostok, Russia

^* To whom correspondence should be addressed.

Received January 28, 2005; Revision received February 18, 2005

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A fucoidanase preparation from the marine mollusk Littorina kurila cleaved some glycosidic bonds in fucoidan from the brown alga Fucus distichus, but neither fucose nor lower oligosaccharides were produced. The main product isolated from the incubation mixture was a polysaccharide built up of disaccharide repeating units →3)-alpha-L-Fucp-(2,4-di-SO₃^-)-(1→4)-alpha-L-Fucp-(2SO₃^-)-(1→, the structure coinciding with the idealized formula proposed for the initial substance. A polymer fraction with the same carbohydrate chain but sulfated only at positions 2 and nonstoichiometrically acetylated at positions 3 and 4 of fucose residues was isolated as a minor component. It is suggested that the native polysaccharide should contain small amounts of non-sulfated and non-acetylated fucose residues, and only their glycosidic bonds are cleaved by the enzyme. The enzymatic hydrolysis showed that irregular regions of the native polysaccharide containing acetylated and partially sulfated repeating units were assembled in blocks.

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KEY WORDS: brown algae, fucoidan, Fucus distichus, fucoidanase, Littorina kurila, marine mollusks

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