Patent ID: 8129148

Claim:
A method for producing a fraction comprising more than 50% of chondroitin represented formula (1), comprising the steps: (a) reacting a glucuronic acid donor, a N-acetylgalactosamine donor, a saccharide acceptor, chondroitin polymerase derived from Escherichia coli K4, and Mn 2+ at a final concentration of 0.02 to 100 mM at 30° C. and pH 7.2 for 5 hours and measuring a chondroitin content ratio, X, in a fraction produced by the reaction, wherein the chondroitin content ratio, X, means a ratio of a number of chondroitin molecules represented by formula (1)/a number of chondroitin molecules represented by formula (2); (b) determining a reaction time for providing the chondroitin content ratio, X, as determined in step (a) in a fraction produced when the reaction is performed under conditions of arbitrary temperature and pH, other than at 30° C. and pH 7.2, at which the chondroitin polymerase derived from Escherichia coli K4 can act for a reaction time defined to be Y; and (c) performing the reaction at the same temperature and pH as step (b) for a time shorter than Y, wherein formulae (1) and (2) are: (GlcA-GalNAc) n (1) GalNAc-(GlcA-GalNAc) n (2) wherein GlcA represents a glucuronic acid residue, GalNac represents an N-acetylgalactosamine residue, - represents a glycosidic bond and n represents an arbitrary integer.