The reaction of sulphite ions with an intermolecular disulphide bond in bovine serum non-mercaptalbumin.

1. The reaction of SO(3) (2-) ions with bovine serum non-mercaptalbumin was studied at physiological pH. 2. The presence of an intermolecular disulphide bond between the protein and one of two small molecules is confirmed. 3. The bonds are readily cleaved according to the equation:AlbS.SR+SO(3) (2-) right harpoon over left harpoon AlbS.SO(3) (-)+RS(-)but the additional presence of 2m-urea is necessary to separate the small molecules from the protein. 4. The points of elution of the small molecules from a column of Sephadex G-25 correspond to those of glutathione and cysteine.