T. B. Ng
Dept. of Biochem., Chinese University of Hong Kong, Hong Kong
Protein-bound polysaccharides, designated as PSK and PSP, have been isolated from the CM-101 strain and the Cov-1 strain, respectively, of the mushroom oriolus versicolor. This article aims at summarizing existing research findings about PSP since information on PSK is well documented.
PSP possesses a molecular weight of approximately 100kDa glutamic and aspartic acids are abundant in its polypeptide component, whereas its polysaccharide component is made up of monosaccharides with arfa-1,4 and beta-1,3 glucosidic linkages. The presence of fucose in PSK and rhamnose and arabinose in PSP distinguishes the two protein-bound polysaccharides, which are otherwise chemically similar.
PSP is classified as a biological response modifier. It induces, in experimental animals, increased gama-interferon production, interleukin-2 production, and T-cell proliferation. It also counteracts the depressive effect of cyclophosphamide on white blood cell count, interleukin-2 production and delayed-type hypersensitivity reaction. Its antipro- liferative activity against tumor cell lenes and in vivo antitumor activity have been demonstrated. A small peptide with a molecular weight of 16-18 kDa originating from PSP has been produced with antiproliferative and antitumor activities.
PSP administered to patients with esophageal cancer, gastric cancer and lung cancer, and who are undergoing radiotherapy or chemotherapy, helps alleviate symptoms and prevents the decline in immune status.
Published on Gen. Pharmac. Vol.30, No.1, pp1-4, 1998
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