PMID-sentid Pub_year Sent_text comp_official_name comp_offsetprotein_name organism prot_offset 825142-3 1976 The overall net negative charge on human J chain was decreased by forming methyl esters of the carboxyl groups, resulting in a sodium dodecyl sulfate determined molecular weight of approximately 17 700. Esters 81-87 joining chain of multimeric IgA and IgM Homo sapiens 41-48