Heterogeneity of component bands in isoelectric focusing patterns

✍ Scribed by John D. Rodwell

• Publisher: Elsevier Science
• Year: 1982
• Tongue: English
• Weight: 886 KB
• Volume: 119
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(82)90611-x

✦ Synopsis

The notion that single bands in isoelectric focusing experiments employing heterogeneous antibody samples are themselves heterogeneous was investigated using both a theoretical and an empirical approach. A computer analysis of the theoretical isoelectric points of 480 unique charged amino acid compositions in the range of those found in antibody V, regions was performed. With a resolution of 0.005 of a pH unit and no vicinal effects on side chain pKs (e.g., urea focusing), this analysis yielded a total of 41 bands of varying heterogeneity. Band heterogeneity was confirmed in an analysis of six different preparatively focused IEF bands from a sample of light chains prepared from antilactose immunoglobulin M. Bands were reduced, alkylated with [3H]iodoacetate and digested with trypsin. Anion and cation exchange chromatography of each digest revealed a pattern of varying heterogeneity for all bands when compared with known homogeneous and heterogeneous controls.