Bound Homocysteine, Cysteine, and Cysteinylglycine Distribution between Albumin

one in serum are covalently bound to proteins via disulfides. Albumin has been considered the dominant binding protein. Methods: Pooled serum and plasma from healthy adults were fractionated into albumin and globulins by affin-ity columns. Content of Hcy, Cys, CysGly, and glutathi-one was determined for serum and plasma fractions and purified proteins by an HPLC method before and after incubation with excess CysGly, Hcy, or glutathione Results: Of protein-bound amino acids in pooled se-rum, 12 % of Hcy, 21 % of Cys, and 33 % of CysGly were bound to globulins, with the remainder bound to albu-min. Slightly higher proportions were bound to globu-lins in pooled plasma. Globulins had 16 % of total exchangeable disulfide and thiol groups in serum base