ISSN:
1611-4663
Keywords:
Lignin-carbohydrate complexes
;
NMR
;
13C tracer
;
Coniferin
;
Ketal linkage
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract In the present study the specifically13C-enriched lignin precursors of biosynthesis (i.e., coniferin-[side chainα−13C], coniferin-[side chain-β−13C] and coniferin-[side chain-γ−13C]) were synthesized and administered exogeneously to ginkgo shoots (Ginkgo biloba L.) to obtain13C-enriched lignin-carbohydrate complexes (LCCs). The specifically13C-enriched LCCs were isolated from the newly formed xylem of ginkgo shoots administered with the13C-enriched precursors and degraded by enzymes. Lignin-rich fractions, so called enzyme-degraded LCCs (EDLCCs), were obtained. By determining their13C-NMR spectra, information related to the chemical structure of lignin building units and linkages between phenylpropane units of lignin and carbohydrates were obtained. It was found that these precursors were incorporated in natural lignin successfully. Three lignin-carbohydrates linkages (i.e., ether type, ester type, ketal type) were found at the C α -position of the side chain of phenylpropane units in ginkgo LCC. No lignin-carbohydrate bond at the Cβ- or Cγ-position of the lignin side chain was observed in the13C-NMR spectra of the13C-enriched LCCs. This fact indicates that a specific13C tracer technique can be useful in NMR study of the chemical structure of LCCs.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00777359
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