Primary structure of human J chain: alignment of peptides from chemical and enzymatic hydrolyses

Biochemistry. 1977 Aug 9;16(16):3507-13. doi: 10.1021/bi00635a002.


The primary structure of the J chain from a human Waldenströms IgM protein has been determined using a combination of automated and conventional Edman degradative procedures. Eighty-five percent of the sequence was established with peptides isolated from tryptic digests of carboxyamidomethylated and citraconylated J chain, many of which were sequenced completely. Alignment of the tryptic fragments was achieved with peptides generated by chymotrypsin and limited acid hydrolyses. The j chain consits of 129 amino acids and a single oligosaccharide structure linked to asparagine at positon 43 of the sequence. The molecular weight, including 7.5% carbohydrate by weight, is 16 422. The location and arrangement of three half-cystines could be deduced from previous studies, whereas the pairing of the remaining five disulfide bonds still needs to be clarified.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Amino Acids / analysis
  • Chemical Phenomena
  • Chemistry
  • Chymotrypsin
  • Humans
  • Hydrolysis
  • Immunoglobulin J-Chains*
  • Peptide Fragments / analysis
  • Trypsin
  • Waldenstrom Macroglobulinemia / immunology


  • Amino Acids
  • Immunoglobulin J-Chains
  • Peptide Fragments
  • Chymotrypsin
  • Trypsin