THE RELATIONSHIP BETWEEN THE MOLECULAR-WEIGHT AND THE ANTICOAGULANT ACTIVITY OF 2 TYPES OF FUCAN SULFATES FROM THE BROWN SEAWEED ECKLONIA-KUROME

Two types of fucan sulfates, galactofucan sulfate and fucoidan, which were isolated separately from the fronds of the brown seaweed Ecklonia Kurome, were fractionated according to molecular weight by gel filtration on a Sepharose CL-6B column. The five galactofucan sulfate subfractions (molecular weights; 10,000 to 79,000) and three fucoidan subfractions (13,000 to 58,000) obtained were composed of fucose, galactose, xylose, glucuronic acid, and sulfate in the approximate molar ratios of 1.00:0.49-0.93:nil-0.08:0.02-0.05:1.56-1.76 and 1.00:0.10-0.21:nil:0.02-0.05:1.42-1.56, respectively. The relationship between the molecular weight and the anticoagulant activity of the two types of fucan sulfates was studied. Both of the fucan sulfates with molecular weights ranging from about 10,000 to 300,000 showed the most potent specific activities in the activated partial thromboplastin time (APTT) assay. In contrast, antithrombin activity of both fucan sulfates was found to be dependent on their molecular weight up to a molecular weight of about 50,000.