N-glycans play a role in physiological functions, including glycoprotein conformation, signal transduction, and antigenicity. Insects display both α-1,6- and α-1,3-linked fucose residues bound to the innermost N-acetylglucosamine of N-glycans whereas core α-1,3-fucosylated N-glycans are not found in mammals. Functions of insect core-fucosylated glycans are not clear, and no α-L-fucosidase related to the N-glycan degradation has been identified. In the genome of the domestic silkworm, Bombyx mori, a gene for a protein, BmFucA, belonging to the glycoside hydrolase family 29 is a candidate for an α-L-fucosidase gene. In this study, BmFucA was cloned and recombinantly expressed as a glutathione-S-transferase tagged protein (GST-BmFucA). Recombinant GST-BmFucA exhibited broad substrate specificity and hydrolyzed p-nitrophenyl α-L-fucopyranoside, 2′-fucosyllactose, 3-fucosyllactose, 3-fucosyl-N,N′-diacetylchitobiose, and 6-fucosyl-N,N′-diacetylchitobiose. Further, GST-BmFucA released fucose from both pyridylaminated complex-type and paucimannose-type glycans that were core-α-1,6-fucosylated. GST-BmFucA also shows hydrolysis activity for core-fucosylated glycans attached to phospholipase A₂ from bee venom. BmFucA may be involved in the catabolism of core-fucosylated N-glycans in B. mori.

N-聚糖在生理功能中起作用，包括糖蛋白构象，信号转导和抗原性。昆虫显示出与N-聚糖的最内层N-乙酰氨基葡糖结合的α-1,6-和α-1,3-连接的岩藻糖残基，而在哺乳动物中未发现核心的α-1,3-岩藻糖基化N-聚糖。昆虫核心岩藻糖基化聚糖的功能尚不清楚，并且尚未鉴定出与N-聚糖降解相关的α-L-岩藻糖苷酶。在家蚕的基因组中，属于糖苷水解酶家族29的蛋白质BmFucA基因Bombyx mori是α-L-岩藻糖苷酶基因的候选基因。在这项研究中，BmFucA被克隆并重组表达为谷胱甘肽-S-转移酶标记的蛋白（GST-BmFucA）。重组GST-BmFucA表现出广泛的底物特异性和水解p硝基苯基α-L-吡喃岩藻糖苷，2 ' -fucosyllactose，3-岩藻糖基，3-岩藻糖基N，N' -diacetylchitobiose，和6-岩藻糖基N，N' -diacetylchitobiose 。此外，GST-BmFucA从吡啶核心复合物α-1,6-岩藻糖基化的吡啶基叠层复合型和低聚甘露糖型聚糖中均释放出岩藻糖。GST-BmFucA还显示了对与蜂毒中磷脂酶A ₂相连的核心岩藻糖基化聚糖的水解活性。BmFucA可能参与家蚕中岩藻糖基化N-聚糖的分解代谢。