Characterisation of a slow component of normal human serum albumin.

A minor component of albumin was isolated from normal human serum. It had reduced electrophoretic mobility, reacted normally with specific albumin antiserum and, in contrast to normal albumin, did not bind nickel. Sequence analysis showed that the minor band contained components with Ala-His-Lys- and His-Lys- N-terminal sequences, indicating removal of Asp and Asp-Ala respectively from the parent albumin which was found to have the expected N-terminal sequence of Asp-Ala-His-Lys. Both normal albumin and the minor component had an average of 0.32 residues of glucose bound as fructosamine.