Structure of Immunoglobulin D: Evidence for the Absence of an Extra Disulfide Bridge in the Fc Fragment

摘要: Abstract Molecular weight determinations of immunoglobulin D suggest the presence an extra region in δ chain. In attempt to locate this region, IgDλ myeloma protein (Gur), was digested with trypsin for 4 min at 56 ° and Fc fragment isolated by ion exchange chromatography. N-terminal analysis showed a heterogeneity site splitting trypsin. The pepsin cysteine containing peptides two dimensional paper high voltage electrophoresis (diagonal map) pH 3.5. Further purification these carried out HVE 6.5 2.1 their amino acid composition partial sequence were determined. Only five cysteic obtained, one corresponding inter heavy-heavy bridge other four, intra chain bridges. This finding would exclude possibility « classical domain » region. position has been arranged based on homology classes immunoglobulins.