Synthesis of 1,5-dideoxy-1,5-imino-d-arabinitol (5-nor-l-fuco-1-deoxynojirimycin) and its application for the affinity purification and characterisation of α-l-fucosidase

✍ Scribed by Günter Legler; Arnold E. Stütz; Hermann Immich

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 871 KB
• Volume: 272
• Category: Article
• ISSN: 0008-6215
• DOI: 10.1016/0008-6215(95)00032-o

✦ Synopsis

The title, 1,5-dideoxy-l,5-imino-D-arabinitol (2), was synthesized in seven steps from Darabinose with 5-azido-5-deoxy-o-arabinofuranose as key intermediate and 40% overall yield. An affinity procedure employing the N-carboxypentyl derivative of 2 linked to aminohexyl agarose permitted the isolation of pure a-L-fucosidase from bovine kidney homogenate in two steps. Inhibition constants of 2 with the purified enzyme ranged from 39/~M (pH 5.0) to 3/zM (pH 7.0) which was ~ 1,500-fold larger than K I for L-fuco-l-deoxynojirimycin (1) at these pH values. A comparably large contribution of the methyl group of I to the inhibition was also indicated by the K l values for D-manno-and L-gulo-l-deoxynojirimycin. The pH-dependence of K I for 1, 2, and other basic analogues was very similar to that of K I for L-fucose (205 /zM at pH 5.0 to 25 gM at pH 7.0). On the other hand, K M for p-nitrophenyl a-L-fucoside and K l for methyl a-L-fucoside showed only small variations with pH. A higher affinity, of up to 100-fold, of the enzyme for L-fUCOSe relative to methyl a-L-fUcoside in conjunction with its different pH-dependence is tentatively explained by a hydrogen bond of the anomeric hydroxyl group as donor with an active site carboxylate with pK a 6.1 as acceptor. The inhibitory potency of 2 was greatly lowered by N,N-dimethylation (K~ 3600/xM at pH 5.0 to 305 /~M at pH 7.0).