A novel method for chemo-enzymatic synthesis of elicitor-active chitosan oligomers and partially N-deacetylated chitin oligomers using N-acylated chitotrioses as substrates in a lysozyme-catalyzed transglycosylation reaction system.
N,N',N"-Tri(monochloro)acetylchitotriose prepared by N-monochloroacetylation of chitotriose trihydrochloride was successfully polymerized into higher-molecular-weight oligomers by a lysozyme-catalyzed transglycosylation reaction, and a following base-catalyzed N-demonochloroacetylation gave a chitosan oligomer mixture mainly composed of oligomers with dp > 6. Partially N-deacetylated chitin oligomers (DAC oligomers) with dp 4-12 were synthesized by the enzyme reaction using N,N',N"-tri(monochloro)acetylchitotriose and N,N',N"-triacetylchitotriose (chitin trimer) as initial substrates followed by N-demonochloroacetylation. The structures of synthetic oligomers were analyzed by 1H NMR spectroscopy, enzymatic hydrolysis and nitrous acid deamination-NaBH4 reduction treatment. The dp of synthetic oligomers was measured by MALDI TOF MS (matrix-assisted laser desorption ionization time-of-flight mass spectrometry) using per-N-acetylated derivatives. The synthetic chitosan and DAC oligomers were strong elicitors for phytoalexin induction in Pisum sativum and Phaseolus vulgaris. This chemo-enzymatic method utilizing N-acylated chitotrioses as substrates is a novel approach to the synthesis of high-molecular-weight chitosan oligomers and DAC oligomers of biological importance.
Akiyama
K
K
Department of Agricultural Science, Okayama University, Japan.
Kawazu
K
K
Kobayashi
A
A
D000107:Acetylation; D001578:Benzopyrans / Q000378:metabolism; D002240:Carbohydrate Sequence; D002686:Chitin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D048271:Chitosan; D007887:Fabaceae / Q000378:metabolism; D006031:Glycosylation; D007529:Isoflavones / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009113:Muramidase / Q000378:metabolism*; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D018532:Pisum sativum / Q000378:metabolism; D010936:Plant Extracts / Q000378:metabolism; D010946:Plants, Medicinal; D036343:Pterocarpans; D012717:Sesquiterpenes; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013729:Terpenes; D014312:Trisaccharides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D000094162:Phytoalexins
D001578:Benzopyrans; D007529:Isoflavones; C098455:N,N',N''-tri(monochloro)acetylchitotriose; D009844:Oligosaccharides; D010936:Plant Extracts; D036343:Pterocarpans; D012717:Sesquiterpenes; D013729:Terpenes; D014312:Trisaccharides; D002686:Chitin; C094208:kievitone; C041161:chitotriose; D048271:Chitosan; D009113:Muramidase; C003161:pisatin; D000094162:Phytoalexins