Cyanogen bromide cleavage of bovine secretory component and its tryptic fragments.
1. Five-domain bovine secretory component and its two-domain and three-domain tryptic fragments have been treated with cyanogen bromide. 2. N-terminal sequence analysis of the purified products showed that cleavage occurred within the disulphide bridged polypeptide loop of domain 2. The site lies within the region that binds IgM and IgA dimers. 3. The relative binding of the CNBr fragments to IgM has been measured and indicates that domains 1 and 3 are directly involved. 4. A possible role for domain 2 is less clear and domains 4 and 5 do not participate in binding.
Beale
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Agricultural and Food Research Council, Institute of Animal Physiology and Genetics Research, Babraham, Cambridge, England.
D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D002417:Cattle; D003488:Cyanogen Bromide / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D007128:Immunoglobulin Fragments / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism*; D012635:Secretory Component / Q000378:metabolism*; D014357:Trypsin / Q000378:metabolism*
D007128:Immunoglobulin Fragments; D010446:Peptide Fragments; D012635:Secretory Component; D014357:Trypsin; D003488:Cyanogen Bromide