Glycosidases of molluscs. Purification and properties of alpha-L-fucosidase from Chamelea gallina L.
An alpha-L-fucosidase had been purified approximately 300-fold from the liver (hepatopancreas) of the marine mollusc Chamelea gallina L. (= Venus gallina L.). During the different steps of the purification procedure it was difficult to remove the contaminant N-acetylglucosaminidase activity; but, after electrofocusing, a final preparation free of this and other glycosidades present in the crude extract was obtained. The purified enzyme has a broad specificity; it hydrolyzes p-nitrophenyl alpha-L-fucoside and natural substrates such as oligosaccharides containing fucosidic residues with alpha 1--2, alpha 1--3 and alpha 1--4 linkages; also it hydrolyzes fucose-containing glycopeptides, such as thyroglobulin glycopeptide, and glycoproteins as procine submaxillary mucin (previously rendered free of sialic acid). The enzyme has a pH optimum of 5.2 +/- 0.2, with a Km of 7 X 10(-5) M using p-nitrophenyl L-fucoside as substrate. It is inhibited by Hg2+ and some sugars, and activated by CN-, Zn2+, Ca2+ and EDTA. It shows two peaks by isoelectric focusing (at 6.3 and 6.6). The molecular weight of the alpha-L-fucosidase by gel filtration was over 2000000.
D000818:Animals; D002413:Cations, Divalent; D003486:Cyanides / Q000494:pharmacology; D004186:Disaccharidases / Q000378:metabolism*; D004355:Drug Stability; D004492:Edetic Acid / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008970:Molecular Weight; D008974:Mollusca / Q000201:enzymology*; D010179:Pancreas / Q000201:enzymology; D005644:alpha-L-Fucosidase / Q000302:isolation & purification / Q000378:metabolism*
D002413:Cations, Divalent; D003486:Cyanides; D004492:Edetic Acid; D004186:Disaccharidases; D005644:alpha-L-Fucosidase