Isolation and characterization of a hyperbranched proteoglycan from Ganoderma Lucidum for anti-diabetes

Presently, an efficient protein tyrosine phosphatase 1B (PTP1B) inhibitor, named FYGL-n, was isolatedfrom Ganoderma Lucidum and characterized for its structure and bioactivity. Structure and chain con-formation of FYGL-n based on both chemical and spectroscopic analysis showed that FYGL-n was ahyperbranched heteropolysaccharide bonded with protein via both serine and threonine residues by O-type glycoside, and showed a sphere observed by AFM. Specifically, monosaccharide compositionindicated that FYGL-n consisted of D-arabinose, D-galactose, L-rhamnose and D-glucose in a mole ratio of 0.08:0.21:0.24:0.47, with a molecular mass of 72.9 kDa. The analysis of amino acids in FYGL-n indicatedthat there were 16 common amino acids, among which aspartic acid, glycine, serine, alanine, glutamicacid and threonine were the dominant components. Also it was demonstrated that FYGL-n could inhibitthe PTP1B activity on a competitive mechanism in vitro.