Specificity patterns of different types of human fucosidase. Recognition of a certain region of the pyranose ring in sugars by the enzymes.

Data on the hydrolysis of fucosides, galactosides and arabinosides by different types of fucosidase are presented. The comparative study of the splitting of alpha-L-fucoside and beta-D-arabinoside with a similar structure at C1--C4 of the pyranose ring and the preparation of the enzyme by affinity chromatography showed that both substrates were hydrolysed by the same enzyme, alpha-L-fucoside(beta-D-arabinoside)hydrolase. The analogous investigation of the hydrolysis of beta-D-fucoside, beta-D-galactoside and alpha-L-arabinoside with a similar structure at C1--C4 of the pyranose ring demonstrated that these glycosides were split by the same enzyne, beta-D-fucoside(beta-D-galactoside, alpha-L-arabinoside)hydrolase, the activity of which is decreased dramatically in GM1-gangliosidosis. The data obtained support the assumption that the specific action of different types of fucosidase is due to recognition by these enzymes of C1--C4 of the pyranose ring in the corresponding substrates. The problems of differential diagnosis of some glycosidoses (focosidosis, GM1-gangliosidosis and Fabry disease) are discussed on the basis of the data obtained.