L-Fucosidases

An enzyme isolated from human liver by ion-exchange chromatography is able to hydrolyse a-L-arabinopyranosides, jS-o-galactopyranosides, jS-o-gluco-pyranosides, and jS-o-xylopyranosides, as well as j8-D-fucopyranosides. The livers from patients with Gaucher s disease were shown to be deficient in iS-D-fucosidase and jS-D-glucosidase activities. 

The a-L-fucosidase activity in cultures of human-skin fibroblasts has been investigated. Ion-exchange chromatography and gel filtration have revealed the presence of different molecular forms of a-L-fucosidase in cultured fibroblasts of human amniotic fluid.  

The molecular weights (2.0 x 10 and 1.4 x 10 ) of two forms of a-L-fucosidase isolated from porcine kidney have been established by gel filtration. Only the former isoenzyme was able to bind to Sephadex by non-specific adsorption. Isoelectric focusing indicated that both forms of the enzyme are heterogeneous. 

Affinity chromatography on a matrix containing residues of 2-amino-2-deoxy-L-fucose has been used to purify an a-L-fucosidase from rat epididymus, giving a preparation that is free from other glycoside hydrolases. The enzyme preparation was used to investigate the structures of L-fucose-containing poly- 

Di Matteo, P. Durand, R. Gatti, A. Maresca, M. Orfeo, F. Urbano, and G. Romeo, 

Human acid jS-D-galactosidase, jS-D-fucosidase, and a-L-arabinofuranosidase appear to have a common identity (see p. 429). 

Decreased binding by the lectins concanavalin A and wheat-germ agglutinin has been found for a number of acidic hydrolases ( 3-D-2-acetamido-2-deoxy-hexosidase, a-L-fucosidase, a- and jS-D-glucosidase, jS-D-galactosidase, and a-D-mannosidase) from skin fibroblasts of three unrelated patients with mucolipidosis II (see p. 423). 

Hoebeke, J. Groswasser, N. Bousard, E. Vamos, and A. D. Strosberg, Arch. Biochem. 

The activity of a-L-fucosidase is decreased in the serum of cystic fibrosis patients compared to age-matched controls.This result, combined with the elevated activity in skin fibroblasts, supports the concept of an intracellular and extracellular distribution of a-L-fucosidase in cystic fibrosis. 

Investigation of the binding characteristics of urinary acid jS-D-galactosidase, j8-D-2-acetamido-2-deoxyglucosidase, a-D-galactosidase, and a-L-fucosidase from patients with mucolipidosis II and mucolipidosis III to agarose-immobilized concanavalin A revealed a two- to ten-fold decrease in the proportion of enzyme (that adsorbed On the lectin) [activities from patients with mucolipidoses II and III (see p. 424)1 

Significant differences occur between the interactions of glycosaminoglycans with a particular lysosomal protein leading to inhibition of lysosomal enzymes including a-o-fucosidase.  

Levels of lysosomal a-L-fucosidase have been determined in normal hair roots and in hair roots obtained from a patient with mannosidosis. The significance of the results was discussed in relation to the levels of other glycoside hydrolyses present and to the detection of lysosomal storage diseases. 

Human liver a-L-fucosidase has been separated into four components by gel filtration and ion-exchange chromatography. These components differed in their relative stabilities to heat and acid and in their response to neuraminidase. The enzymes were able to liberate L-fucose from 2 -L-fucosyl-lactose. The serum enzyme was also investigated. 

The chemical relationship of the seven forms of human liver a-L-fucosidase has been studied by isoelectric focusing of neuraminidase and sialyltransferase-treated preparations of a-L-fucosidase. Neuraminidase treatment leads to a decrease in the activity of the more-acidic forms, and a concomitant increase in the activity of the more-neutral forms. Incubation of the neuraminidase-treated enzyme forms with a radiolabelled CMP-neuraminic acid and sialyl-transferase led to generation of more-acidic forms of the enzyme. The seven isoenzymes were separated by preparative isoelectric focusing and were characterized kinetically and immunochemically. 

Human serum a-L-fucosidase has been purified 240 000 fold with 35 % yield by an affinity chromatographic procedure utilizing agarose-immobilized 2-amino-2-deoxy-L-fucose. Isoelectric focusing of the purified enzyme indicated the presence of several forms (major form p/ 5.0). Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of the enzyme (mol. wt. 2.96 0.30 X 10 by gel filtration) indicated that the presence of two subunits with similar molecular weights (5.65 x 10 and 5.40 x 10 ). Using the 4-nitro-phenyl substrate (Xm value 0.52 mM) the enzyme displayed a broad pH optimum centred round pH 4.8 with a second minor optimum at pH 6.1. The enzyme was shown to contain 1.7% neuraminic acid quantitative immuno-precipitation studies were also conducted on the enzyme. 

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The guanidino analogue 90 of the 7-membered cyclic urea system was prepared, enantiomerically pure, from D-mannitol. The derivative 90 selectively inhibits bovine kidney a-L-fucosidase at 2.8pM <00BMC307>. 

Instead of a triflate, the electrophile on the glycosyl acceptor can be an a,(3-unsaturated carbonyl group. This is the case reported in Fig. 25, in which a stereoselective Michael addition of the 1-thiosugar 56 to the a,(3-conjugated system of levoglucosenone 57, generated after deprotection a couple of L-fucopyranosyl-4-thiodisaccharides 61 and 62 presenting inhibitory activity on a-L-fucosidase.54... 

Selected from among their contributions were the first example of a synthetic furanoid iminoalditol, l,4-dideoxy-l,4-imino-D-mannitol (19, Scheme 7) 49 the first synthesis of the powerful L-fucosidase inhibitor l,5-dideoxy-l,5-imino-L-fucitol (20),50 the synthesis and structure confirmation of l,4-dideoxy-l,4-imino-D-arabinitol... 

The inverting GH 95 1,2-oc-L-fucosidase (EC 3.2.1.63) from Bifidobacterium bifi-dum in complex (PDB 2EAC) with 1-deoxy-L-fuconojirimycin (20) showed the inhibitor in C4 chair conformation, resembling L-fucose and the entrance to the active site was narrowed by the gate keeper loops.315 A calcium ion associated with the protein was not involved in the catalytic process but was considered to stabilize the enzyme. 

A. Lammerts van Bueren, A. Ardevol, J. Fayers-Kerr, B. Luo, Y. Zhang, M. Sollogoub, Y. Bleriot, C. Rovira, and G. J. Davies, Analysis of the reaction coordinate of a-L-fucosidases A combined structural and quantum mechanical approach,./. Am. Chem. Soc., 132 (2010) 1804-1806. 

M. Nagae, A. Tsuchiya, T. Katayama, K. Yamamoto, S. Wakatsuki, and R. Kato, Structural basis of the catalytic reaction mechanism of novel 1,2-a-L-fucosidase from Bifidobacterium bifidum, J. Biol. Chem., 282 (2007) 18497-18509. 

The inhibitory activity of compound (42) (Scheme 13) was examined during the hydrolysis of p-nitrophenyl a-L-fucopyranoside by a-L-fucosidases. As reported above, this compound showed mixed inhibition [32]. 

In the series of a-L-fucopyranosyl-thio-glycosides, the most powerful inhibitor of a-L-fucosidases was the a(l ->3) linked isomer obtained by deprotection of the disaccharide (65 b). It has been shown to be a competitive inhibitor (Kj= 0.65 mmol/1) [32]. 

Less active derivatives might therefore be desirable in some cases. In this context, Paulsen and co-workers synthesized a range of chain-extended as well as bicyclic analogues of 1-deoxyfuconojirimydn, amongst others the 6-C-ethyl (54) and 6-C-methyl derivatives as well as l-deoxy-6,7,8-a-tri-epi-castanosper-mine (55). All of these derivatives exhibited considerable inhibitory activities towards a-L-fucosidase and were slightly to appreciably less active than the parent compound [107]. In an attempt to design a simple synthesis of 1-deoxy-... 

An amidrazone (58) derived from 5-amino-5-deoxy-L-fuconolactam was found to inhibit a recombinant human a-L-fucosidase with a K -value of 820 nmol/1 [ 111 ]. A simple synthesis of 1,5-dideoxy-1,5-imino-D-arabinitol (59), previously prepared by Ganem et al. [49] as a potential maimosidase inhibitor, was applied to the affinity purification of a-L-fucosidase from bovine kidney by an improved method and the characterization of the enzyme thus obtained [112]. The relatively low affinity of this compound to the enzyme (Kj 2.2 pmol/1 at pH 7) compared to 1-deoxyfuconoJirimycin (51) turned out to be advantageous in terms of enzyme recovery and yield. Structurally related, suitably protected 5-amino-5-deoxy-D-arabinopyranose (60), was coupled with a N-acetyl-6-deoxy-6-thio-D-glucosaminide (61) to give a stable thioglycoside (62) [113]. 

A L-/wco-related analogue (71) of isofagomine [61], which was recently prepared from D-ribose by Ichikawa et al. following previously established chemistry [63,121], was found to be an a-L-fucosidase inhibitor with Kj 8 pmol/1. No inhibition was found with tetrazole derivatives such as (72) [ 122] obtained from L-gulonolactone. 

Fucosidase inhibiting l,4,5-trideoxy-l,4-imino-L-lyxitol (78) was prepared [124] from D-ribose via protected 5-amino-5-deoxy-L-lyxose (79) by a chemical route. This compound, as well as the 1-aminomethyl homologue (80), obtained by Kiliani-Fischer chain extension of (79), inhibited a-L-fucosidase with K around 2 pmol/1. l,4-Dideoxy-l,4-imino-D-iditol (81) [71] was found to be a moderate inhibitor of the enzyme. 

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