SYNTHESIS AND CHARACTERIZATION OF TYRAMINE-DERIVATIZED (1-]4)-LINKED ALPHA-D-OLIGOGALACTURONIDES

The reducing end C-l of (1 --> 4)-linked alpha-D-oligogalacturonides ( oligogalacturonides), with degrees of polymerization (dp) 3 and 13, wa s coupled to tyramine via reductive amination in the presence of sodiu m cyanoborohydride. These derivatives were purified in milligram quant ities and structurally characterized. Tyramination of trigalacturonic acid proceeded to completion. The yield of apparently homogeneous tyra minated trigalacturonic acid after desalting was 35%, Derivatization o f tridecagalacturonide with tyramine was incomplete, The tyraminated t ridecagalacturonide was purified to apparent homogeneity using semipre parative high-performance anion-exchange chromatography (HPAEC) with a yield of 30%. The structures of the derivatized oligogalacturonides w ere established by H-1 NMR spectroscopy and electrospray mass spectrom etry. (C) 1996 Elsevier Science Ltd.