<；P>；PROBLEM TO BE SOLVED: To provide a fat precursor cell differentiation inhibitor which becomes an antiobestic agent and to provide a method for producing the inhibitor. <；P>；SOLUTION: The fat precursor cell differentiation inhibitor comprises an O-acyl derivative of acid mucopolysaccharide WAK-1-A which marine bacteria Pseudomonas sp. produces as an active ingredient. The structural formula of the compound is composed of recurring units of three molecules of N-acetylgalactosamine, one molecule of glucuronic acid and one molecule of pyruvic acid. The WAK-1-A can be obtained by extracting WAK-1-A with a liquid from a culture solution and repeating steps adding an alcohol, etc, to the liquid to form a precipitate and dissolving the precipitate into the liquid and adding the alcohol, etc., thereto again to form the precipitate, dialyzing the precipitate with water and drying the dialyzed material by spray, etc. <；P>；COPYRIGHT: (C)2007,JPO&INPIT
