Abstract
Galactosaminoglycan (CO-N), prepared from the culture filtrate of Cordyceps ophioglossoides, aggregated the sera from cancer patients, but not those from healthy donors. The results of sodium dodecyl sulfate polyacrylamide gel electrophoresis, polyacrylamide gel isoelectric focusing, and single radial immunodiffusion revealed that the aggregate mainly consisted of haptoglobin, albumin, α1-acid glycoprotein, α1-antitrypsin, hemopexin, and CO-N itself.
The pre-addition of h-CO-N (Mr ca. 10000, polygalactosamine obtained by partial acid hydrolysis of CO-N) resulted in inhibition of the aggregation by CO-N. Desialylation of the serum by neuraminidase treatment also resulted in inhibition of the aggregation. Further h-CO-N, N-acetylated CO-N, chitosan, or diethylaminoethyl-dextran instead of CO-N was added to the serum, the aggregation was not observed. When α1-acid glycoprotein was added to the serum from healthy donor, the aggregation by CO-N was observed, while haptoglobin or α1-antitrypsin did not cause aggregation. These results suggested that the binding between galactosaminyl residues of CO-N and sialic acids at non-reducing ends of sugar chains of serum glycoproteins might be required as the essential step to the aggregation by CO-N.
