Gossypol binds to a high-affinity binding site on human serum albumin

The triterpene gossypol competes with bilirubin for a high-affinity binding site on human serum albumin. Similar competition between bilirubin and gossypol occurs in the binding of these ligands to the glutathione S-transferases from human liver and placenta. In each case, gossypol and bilirubin exhibit similar binding constants. The binding properties of gossypol may generally mimic those of bilirubin.