The molecular abnormality of albumin Parklands: 365 Asp----His.

An electrophoretically slow albumin variant was isolated from the plasma of a patient with bisalbuminemia. Reverse-phase peptide mapping revealed a single altered peak when tryptic digests of the normal and variant albumin were compared. After rechromatography and amino acid analysis, a sequence/composition of Cys-Cys-Ala-Ala-Ala-His-Pro,His,Glu,Cys,Tyr,Ala,Lys was obtained for the mutant peptide, while a sequence of Cys-Cys-Ala-Ala-Ala-Asp-Pro-His-Glu-Cys-Tyr,Ala,Lys was obtained for the normal peptide. This establishes the mutation as 365 Asp----His and the new albumin has been named albumin Parklands. Interestingly, this mutation results in the loss of the single Asp-Pro bond that is normally present between residues 365 and 366. Predictably, this confers on albumin Parklands a greater resistance to partial acid hydrolysis, a feature which, when employed together with SDS-gel electrophoresis, can be used as a diagnostic test for the presence of this variant.