Specific degradation of pectins via a carbodiimide-mediated Lossen rearrangement of methyl esterified galacturonic acid residues
2001; Elsevier BV; Volume: 333; Issue: 1 Linguagem: Inglês
10.1016/s0008-6215(01)00120-3
ISSN1873-426X
AutoresPaul W. Needs, Neil M. Rigby, Stephen G. Ring, Alistair MacDougall,
Tópico(s)Enzyme Production and Characterization
ResumoA specific, chemical degradation of the methyl esterified galacturonic acid residues of pectins is described. These residues are converted, with hydroxylamine, to hydroxamic acids, and then, with a carbodiimide, to isoureas; the latter undergo a Lossen rearrangement on alkaline hydrolysis. The isocyanates formed are hydrolysed to 5-aminoarabinopyranose derivatives, which spontaneously ring open to give 1,5-dialdehydes. The latter are reduced, in situ, to avoid peeling reactions, with sodium borohydride to give substituted arabitol residues. Thus, overall, partially esterified pectins are specifically cleaved to generate a series of oligogalacturonic acids bearing an arabitol residue as aglycone. Analysis of oligomers so generated discloses the pattern of contiguous nonesterification in a variety of pectins of differing degrees of esterification. Other potential applications are described.
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