PubMed:1773428 JSONTXT

{"target":"https://pubannotation.org/docs/sourcedb/PubMed/sourceid/1773428","sourcedb":"PubMed","sourceid":"1773428","source_url":"http://www.ncbi.nlm.nih.gov/pubmed/1773428","text":"Determination of the degree of N-acetylation and the distribution of N-acetyl groups in partially N-deacetylated chitins (chitosans) by high-field n.m.r. spectroscopy.\nThe composition and sequence of 2-acetamido-2-deoxy-beta-D-glucose (GlcNAc) and 2-amino-2-deoxy-beta-D-glucose (GlcN) residues in partially N-deacetylated chitosans, prepared under homogeneous and heterogeneous conditions, have been determined by 1H-n.m.r. spectroscopy. It was necessary to depolymerise the chitosan slightly by treatment with nitrous acid before spectroscopy. A sequence-dependent deshielding of H-1 of the GlcNAc residues made it possible to determine the proportions of the four possible diads. Chitosan prepared by N-deacetylation under homogeneous conditions gave values for the diad frequencies that were roughly consistent with a random distribution of the N-acetyl groups. Samples prepared under heterogeneous conditions have a frequency of the GlcNAc-GlcNAc diad slightly higher than for a random (Bernoullian) distribution. The chitosans, prepared under both homogeneous and heterogeneous conditions, with a degree of acetylation of 50% were soluble at neutral pH.","tracks":[{"project":"sentences","denotations":[{"id":"TextSentencer_T1","span":{"begin":0,"end":167},"obj":"Sentence"},{"id":"TextSentencer_T2","span":{"begin":168,"end":438},"obj":"Sentence"},{"id":"TextSentencer_T3","span":{"begin":439,"end":545},"obj":"Sentence"},{"id":"TextSentencer_T4","span":{"begin":546,"end":682},"obj":"Sentence"},{"id":"TextSentencer_T5","span":{"begin":683,"end":865},"obj":"Sentence"},{"id":"TextSentencer_T6","span":{"begin":866,"end":1018},"obj":"Sentence"},{"id":"TextSentencer_T7","span":{"begin":1019,"end":1159},"obj":"Sentence"},{"id":"T1","span":{"begin":0,"end":167},"obj":"Sentence"},{"id":"T2","span":{"begin":168,"end":438},"obj":"Sentence"},{"id":"T3","span":{"begin":439,"end":545},"obj":"Sentence"},{"id":"T4","span":{"begin":546,"end":682},"obj":"Sentence"},{"id":"T5","span":{"begin":683,"end":865},"obj":"Sentence"},{"id":"T6","span":{"begin":866,"end":1018},"obj":"Sentence"},{"id":"T7","span":{"begin":1019,"end":1159},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"attributes":[{"subj":"TextSentencer_T1","pred":"source","obj":"sentences"},{"subj":"TextSentencer_T2","pred":"source","obj":"sentences"},{"subj":"TextSentencer_T3","pred":"source","obj":"sentences"},{"subj":"TextSentencer_T4","pred":"source","obj":"sentences"},{"subj":"TextSentencer_T5","pred":"source","obj":"sentences"},{"subj":"TextSentencer_T6","pred":"source","obj":"sentences"},{"subj":"TextSentencer_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":"NGLY1-deficiency","denotations":[{"id":"PD-NGLY1-deficiency-B_T1","span":{"begin":236,"end":242},"obj":"chem:24139"},{"id":"PD-NGLY1-deficiency-B_T2","span":{"begin":593,"end":599},"obj":"chem:24139"},{"id":"PD-NGLY1-deficiency-B_T3","span":{"begin":938,"end":944},"obj":"chem:24139"},{"id":"PD-NGLY1-deficiency-B_T4","span":{"begin":945,"end":951},"obj":"chem:24139"}],"namespaces":[{"prefix":"hgnc","uri":"https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:"},{"prefix":"omim","uri":"https://www.omim.org/entry/"},{"prefix":"chem","uri":"https://pubchem.ncbi.nlm.nih.gov/compound/"}],"attributes":[{"subj":"PD-NGLY1-deficiency-B_T1","pred":"source","obj":"NGLY1-deficiency"},{"subj":"PD-NGLY1-deficiency-B_T2","pred":"source","obj":"NGLY1-deficiency"},{"subj":"PD-NGLY1-deficiency-B_T3","pred":"source","obj":"NGLY1-deficiency"},{"subj":"PD-NGLY1-deficiency-B_T4","pred":"source","obj":"NGLY1-deficiency"}]},{"project":"GlyCosmos6-Glycan-Motif-Structure","denotations":[{"id":"T1","span":{"begin":227,"end":234},"obj":"https://glytoucan.org/Structures/Glycans/G15021LG"},{"id":"T2","span":{"begin":271,"end":278},"obj":"https://glytoucan.org/Structures/Glycans/G15021LG"}],"attributes":[{"subj":"T1","pred":"source","obj":"GlyCosmos6-Glycan-Motif-Structure"},{"subj":"T2","pred":"source","obj":"GlyCosmos6-Glycan-Motif-Structure"}]},{"project":"GlyCosmos6-Glycan-Motif-Image","denotations":[{"id":"T1","span":{"begin":227,"end":234},"obj":"Glycan_Motif"},{"id":"T2","span":{"begin":271,"end":278},"obj":"Glycan_Motif"}],"attributes":[{"id":"A1","pred":"image","subj":"T1","obj":"https://api.glycosmos.org/wurcs2image/0.10.0/png/binary/G15021LG"},{"id":"A2","pred":"image","subj":"T2","obj":"https://api.glycosmos.org/wurcs2image/0.10.0/png/binary/G15021LG"},{"subj":"T1","pred":"source","obj":"GlyCosmos6-Glycan-Motif-Image"},{"subj":"T2","pred":"source","obj":"GlyCosmos6-Glycan-Motif-Image"}]}],"config":{"attribute types":[{"pred":"source","value type":"selection","values":[{"id":"sentences","color":"#93ec9d","default":true},{"id":"NGLY1-deficiency","color":"#ec93a2"},{"id":"GlyCosmos6-Glycan-Motif-Structure","color":"#93bcec"},{"id":"GlyCosmos6-Glycan-Motif-Image","color":"#d6ec93"}]}]}}