Human α‐<i>N</i>‐Acetylglucosaminidase

K, von Figura

doi:10.1111/j.1432-1033.1977.tb11909.x

Cited by 35 publications

(17 citation statements)

References 31 publications

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“…a-L-iduronidase [23], arylsulphatase B [35,36], a-N-acetylglucosaminidase [37], sulphoiduronate sulphohydrolase (J. Bielicki, P. R. Clements & J. J. Hopwood, unpublished work) and ,-N-acetylhexosaminidase [38]} or in the degradation of other glycoconjugates [39,40] have been reported. Cheng et al [40] purified and identified two forms of cx-D-mannosidase from human liver that differed in both their subunit composition and their ability to be taken up into cultured human skin fibroblasts.…”

Section: Discussionmentioning

confidence: 99%

Human liver N-acetylglucosamine-6-sulphate sulphatase. Purification and characterization

Freeman

Clements

Hopwood

1987

Biochemical Journal

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Human N-acetylglucosamine-6-sulphate sulphatase was purified at least 50000-fold to homogeneity in 780%yield from liver with a simple three-step four-column procedure, which consists of a concanavalin A-Sepharose/Blue A-agarose coupled step, chromatofocusing and Cu2+-chelating Sepharose chromatography. In all, four forms were isolated and partially characterized. Forms A and B, both with a pl greater than 9.5 and representing 30% and 60% respectively of the recovered enzyme activity, were separated by hydroxyapatite chromatography of the enzyme preparation obtained from the Cu2+-chelating Sepharose step. Both forms A and B had native molecular masses of 75 kDa. When analysed by SDS/polyacrylamide-gel electrophoresis, form A consists of a single polypeptide of molecular mass 78 kDa, whereas form B contained 48 kDa and 32 kDa polypeptide subunits. Neither form A nor form B was taken up from the culture medium into cultured human skin fibroblasts. The two other forms (C and D), with pI values of 5.8 and 5.4 respectively, represented approx. 7% and 3% of the total recovered enzyme activity. The native molecular masses of forms C and D were 94 kDa and approx. 75 kDa respectively. Form C contained three polypeptides with molecular masses of 48, 45 and 32 kDa. N-Acetylglucosamine-6-sulphate sulphatase activity was measured with a radiolabelled disaccharide substrate derived from heparin. The development of this substrate enabled the isolation and characterization of N-acetylglucosamine-6-sulphate sulphatase to proceed efficiently. Forms A, B and C had pH optima of 5.0, Km values of 11.7, 14.2 and 11.1 LM respectively and Vmax values of 105, 60 and 53 nmol/min per mg of protein respectively. The molecular basis of the multiple forms of this sulphatase is not known. It is postulated that the differences in structure and properties of the four enzyme forms are due to differences in the state of processing of a large subunit.

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Section: Discussionmentioning

confidence: 99%

Human liver N-acetylglucosamine-6-sulphate sulphatase. Purification and characterization

Freeman

Clements

Hopwood

1987

Biochemical Journal

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“…These results suggest that this enzyme acts optimally under intestinal conditions (pH 7.0 -7.5), which are noticeably different from the optimal conditions of human ␣GNase (i.e. pH 4.5-5.0), a lysosomal glycosidase (18,19).…”

Section: Molecular Cloning and Expression Of Full-length And Truncatementioning

confidence: 69%

Glycoside Hydrolase Family 89 α-N-acetylglucosaminidase from Clostridium perfringens Specifically Acts on GlcNAcα1,4Galβ1R at the Non-reducing Terminus of O-Glycans in Gastric Mucin

Fujita

Tsuchida

Hirata

et al. 2011

Journal of Biological Chemistry

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In mammals, ␣-linked GlcNAc is primarily found in heparan sulfate/heparin and gastric gland mucous cell type mucin. ␣-N-Acetylglucosaminidases (␣GNases) belonging to glycoside hydrolase family 89 are widely distributed from bacteria to higher eukaryotes. Human lysosomal ␣GNase is well known to degrade heparin and heparan sulfate. Here, we reveal the substrate specificity of ␣GNase (AgnC) from Clostridium perfringens strain 13, a bacterial homolog of human ␣GNase, by chemically synthesizing a series of disaccharide substrates containing ␣-linked GlcNAc. AgnC was found to release GlcNAc from GlcNAc␣1,4Gal␤1pMP and GlcNAc␣1pNP substrates (where pMP and pNP represent p-methoxyphenyl and p-nitrophenyl, respectively). AgnC also released GlcNAc from porcine gastric mucin and cell surface mucin. Because AgnC showed no activity against any of the GlcNAc␣1,2Gal␤1pMP, GlcNAc␣1,3Gal␤1pMP, GlcNAc␣1,6Gal␤1pMP, and GlcNAc␣1,4GlcA␤1pMP substrates, this enzyme may represent a specific glycosidase required for degrading ␣-GlcNAccapped O-glycans of the class III mucin secreted from the stomach and duodenum. Deletion of the C-terminal region containing several carbohydrate-binding module 32 (CBM32) domains significantly reduced the activity for porcine gastric mucin; however, activity against GlcNAc␣1,4Gal␤1pMP was markedly enhanced. Dot blot and ELISA analyses revealed that the deletion construct containing the C-terminal CBM-C2 to CBM-C6 domains binds strongly to porcine gastric mucin. Consequently, tandem CBM32 domains located near the C terminus of AgnC should function by increasing the affinity for branched or clustered ␣-GlcNAc-containing glycans. The agnC gene-disrupted strain showed significantly reduced growth on the class III mucin-containing medium compared with the wild type strain, suggesting that AgnC might have an important role in dominant growth in intestines.

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“…Since these residues are unique to heparan sulfate and heparan, it is plausible that deficiency of each of these enzymes results in the intralysosomal storage of heparan sulfate-like fragments and their increased urinary excretion. At their non-reducing terminals these fragments bear predominantly N-sulfoglucosaminyl residues (Sanfilippo type A), N-acetylglucosaminyl residues (Sanfilippo type B) or glucosaminyl residues (Sanfilippo type C) (Kresse et al, 1977;von Figura, 1977).…”

Section: Discussionmentioning

confidence: 99%

Sanfilippo type C disease: Clinical findings in four patients with a new variant of mucopolysaccharidosis III

et al. 1979

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A new genetic variant of the Sanfilippo syndrome due to deficiency of acetyl CoA: alpha-glucosaminide N-acetyltransferase, was recently demonstrated in four patients. The clinical findings of these patients are reported here. Differential diagnosis from other types of the Sanfilippo syndrome on clinical and routine laboratory criteria is difficult and enzyme assay is necessary to reach the diagnosis. Since two of the patients reported are females and consanguinity was present in one case, autosomal recessive inheritance is most probable.

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Human α‐N‐Acetylglucosaminidase

Cited by 35 publications

References 31 publications

Human liver N-acetylglucosamine-6-sulphate sulphatase. Purification and characterization

Human liver N-acetylglucosamine-6-sulphate sulphatase. Purification and characterization

Glycoside Hydrolase Family 89 α-N-acetylglucosaminidase from Clostridium perfringens Specifically Acts on GlcNAcα1,4Galβ1R at the Non-reducing Terminus of O-Glycans in Gastric Mucin

Sanfilippo type C disease: Clinical findings in four patients with a new variant of mucopolysaccharidosis III

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