Purification and properties of two forms of human α-L-fucosidase

doi:10.1016/0005-2744(80)90237-5

淡江大學機構典藏 > 理學院 > 化學學系暨研究所 > 期刊論文 > Item 987654321/61701

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Title:	Purification and properties of two forms of human α-L-fucosidase
Authors:	Chien, Su-fang;Dawson, Glyn
Contributors:	淡江大學化學學系
Date:	1980-01-01
Issue Date:	2013-05-31 11:34:19 (UTC+8)
Publisher:	Amsterdam: Elsevier BV
Abstract:	High (100 000) and low (50 000) molecular weight forms of α-L-fucosidase (α-fucosidase I and II) were purified to apparent homogeneity from human spleen, liver, brain and kidney on the basis of differential affinity for ε-amino-caproyl fucosamine-agarose bead columns. α-Fucosidase I (the 'bound' form) consisted of two 50 000 dalton monomers; however, both forms can aggregate to tetramer and hexamer forms. Most previous studies on α-fucosidase have been carried out on this form of human α-fucosidase although the bound and unbound forms of the enzyme were present in equal amounts in human spleen. The bound (100 000) form is a sialoglycoprotein whereas the unbound (50 000) form, is a neutral mannose-rich glycoprotein. Other differences with respect to amino acid composition, pH optimum, electrophoretic mobility, K(m), thermal stability, and natural substrate specificities were observed. All preparations hydrolysed 4-methylumbelliferyl-α-L-fucoside, fucosyllactose, and lacto-N-fucopentaose I, but the unbound fraction (α-fucosidase II) preferentially hydrolysed lacto-N-fucopentaose II. The unbound (mannose-rich) α-fucosidase II was taken up by human skin fibroblasts with higher affinity (5% per 2 h per 2.105 cells) than the bound (sialo-) α-fucosidase I (<1% per 2.105 cells). Uptake was inhibited by other lysosomal hydrolases, fetal calf serum, mannose 6-phosphate and phosphomannans and to a lesser extent by heparins. Our studies suggest that α-fucosidase I is not a simple dimer of α-fucosidase II and represents a less-biologically active form of the enzyme.
Relation:	Biochimica Et Biophysica Acta. General Subjects 614(2), pp.476-488
DOI:	10.1016/0005-2744(80)90237-5
Appears in Collections:	[化學學系暨研究所] 期刊論文

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