PubMed:7506257 JSONTXT

{"target":"https://pubannotation.org/docs/sourcedb/PubMed/sourceid/7506257","sourcedb":"PubMed","sourceid":"7506257","source_url":"https://www.ncbi.nlm.nih.gov/pubmed/7506257","text":"Location of a novel type of interpolypeptide chain linkage in the human protein HC-IgA complex (HC-IgA) and identification of a heterogeneous chromophore associated with the complex.\nProtein HC (human complex-forming glycoprotein, heterogeneous in charge) is a member of the lipocalin superfamily of hydrophobic ligand-binding proteins. The quantitatively dominating blood plasma form of protein HC is a protein HC-IgA complex (HC-IgA), which is the fourth most abundant immunoglobulin species in plasma. A photodiode array detection system on-line with a high performance liquid chromatograph has allowed the identification of low amounts of a heterogeneous fluorescent chromophore covalently bound to HC-IgA, and displaying significant absorption in the visible region in resemblance to the free protein HC chromophore. Several structurally related chromophore-containing linked peptides, carrying 80% of the light absorption at 330 nm of HC-IgA, were isolated from a pepsin-produced protein HC-alpha 1-nonapeptide. Sequence analysis of these linked peptides demonstrated that the bond between protein HC and IgA represents a novel type of reduction-resistant linkage between polypeptide chains and involves the cysteine residue 34 of protein HC and the penultimate cysteine residue of the carboxyl-terminal part of one of the IgA heavy chains, as well as the heterogeneous fluorescent chromophore. The light absorption and fluorescent spectra of the chromophore-linked peptides were similar to those of native free protein HC.","tracks":[{"project":"sentences","denotations":[{"id":"T1","span":{"begin":0,"end":182},"obj":"Sentence"},{"id":"T2","span":{"begin":183,"end":336},"obj":"Sentence"},{"id":"T3","span":{"begin":337,"end":504},"obj":"Sentence"},{"id":"T4","span":{"begin":505,"end":821},"obj":"Sentence"},{"id":"T5","span":{"begin":822,"end":1017},"obj":"Sentence"},{"id":"T6","span":{"begin":1018,"end":1400},"obj":"Sentence"},{"id":"T7","span":{"begin":1401,"end":1529},"obj":"Sentence"},{"id":"T1","span":{"begin":0,"end":182},"obj":"Sentence"},{"id":"T2","span":{"begin":183,"end":336},"obj":"Sentence"},{"id":"T3","span":{"begin":337,"end":504},"obj":"Sentence"},{"id":"T4","span":{"begin":505,"end":821},"obj":"Sentence"},{"id":"T5","span":{"begin":822,"end":1017},"obj":"Sentence"},{"id":"T6","span":{"begin":1018,"end":1400},"obj":"Sentence"},{"id":"T7","span":{"begin":1401,"end":1529},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"attributes":[{"subj":"T1","pred":"source","obj":"sentences"},{"subj":"T2","pred":"source","obj":"sentences"},{"subj":"T3","pred":"source","obj":"sentences"},{"subj":"T4","pred":"source","obj":"sentences"},{"subj":"T5","pred":"source","obj":"sentences"},{"subj":"T6","pred":"source","obj":"sentences"},{"subj":"T7","pred":"source","obj":"sentences"},{"subj":"T1","pred":"source","obj":"sentences"},{"subj":"T2","pred":"source","obj":"sentences"},{"subj":"T3","pred":"source","obj":"sentences"},{"subj":"T4","pred":"source","obj":"sentences"},{"subj":"T5","pred":"source","obj":"sentences"},{"subj":"T6","pred":"source","obj":"sentences"},{"subj":"T7","pred":"source","obj":"sentences"}]},{"project":"Glycosmos6-MAT","denotations":[{"id":"T1","span":{"begin":367,"end":379},"obj":"http://purl.obolibrary.org/obo/MAT_0000052"},{"id":"T2","span":{"begin":367,"end":372},"obj":"http://purl.obolibrary.org/obo/MAT_0000083"},{"id":"T3","span":{"begin":367,"end":372},"obj":"http://purl.obolibrary.org/obo/MAT_0000315"}],"attributes":[{"subj":"T1","pred":"source","obj":"Glycosmos6-MAT"},{"subj":"T2","pred":"source","obj":"Glycosmos6-MAT"},{"subj":"T3","pred":"source","obj":"Glycosmos6-MAT"}]},{"project":"NCBITAXON","denotations":[{"id":"T1","span":{"begin":66,"end":71},"obj":"OrganismTaxon"},{"id":"T2","span":{"begin":195,"end":200},"obj":"OrganismTaxon"}],"attributes":[{"id":"A1","pred":"db_id","subj":"T1","obj":"9606"},{"id":"A2","pred":"db_id","subj":"T2","obj":"9606"},{"subj":"T1","pred":"source","obj":"NCBITAXON"},{"subj":"T2","pred":"source","obj":"NCBITAXON"}]},{"project":"Anatomy-MAT","denotations":[{"id":"T1","span":{"begin":367,"end":379},"obj":"Body_part"}],"attributes":[{"id":"A1","pred":"mat_id","subj":"T1","obj":"http://purl.obolibrary.org/obo/MAT_0000052"},{"subj":"T1","pred":"source","obj":"Anatomy-MAT"}]},{"project":"Anatomy-UBERON","denotations":[{"id":"T1","span":{"begin":367,"end":379},"obj":"Body_part"},{"id":"T2","span":{"begin":497,"end":503},"obj":"Body_part"}],"attributes":[{"id":"A1","pred":"uberon_id","subj":"T1","obj":"http://purl.obolibrary.org/obo/UBERON_0001969"},{"id":"A2","pred":"uberon_id","subj":"T2","obj":"http://purl.obolibrary.org/obo/UBERON_0001969"},{"subj":"T1","pred":"source","obj":"Anatomy-UBERON"},{"subj":"T2","pred":"source","obj":"Anatomy-UBERON"}]}],"config":{"attribute types":[{"pred":"source","value type":"selection","values":[{"id":"sentences","color":"#bc93ec","default":true},{"id":"Glycosmos6-MAT","color":"#93eca2"},{"id":"NCBITAXON","color":"#ec939d"},{"id":"Anatomy-MAT","color":"#93b7ec"},{"id":"Anatomy-UBERON","color":"#d1ec93"}]}]}}