Binding of Glycyrrhizin to Human Serum and Human Serum Albumin

抄録

The binding of glycyrrhizin (GLZ) to human serum and human serum albumin (HSA) was examined by an ultrafiltration technique. Specific and nonspecific bindings were observed in both human serum and HSA. The association constants (K) for the specific binddings were very similar : 1.31×10⁵M^-1 in human serum and 3.87×10⁵M^-1 in HSA. The number of binding sites (n) and the linear binding coefficient (Φ) in HSA were 1.95 and 3.09×10³M^-1, respectively.When the human serum protein concentration ws assumed to be 4.2% (equal to the measured serum albumin concentration), n in human serum was 3.09, which is similar to the n value in HSA, and Φ in human serum was 0.71×10³M^-1, which is reasonably close to that for HSA. The binding pattern of GLZ with human serum protein on Sephadex G-200 column chromatography showed that GLZ binds to only the albumin fraction.It was concluded that the GLZ-binding sites in human serum exist mainly on albumin and GLZ binds to specific and nonspecific binding sites at lower and higher concentrations that approximately 2mM, respectively.