An assay for iduronate sulfatase (hunter corrective factor)

doi:10.1016/S0008-6215(00)87067-6

Carbohydrate Research

Volume 37, Issue 1, October 1974, Pages 103-109

Dedicated to the memory of Professor W.Z. Hassid.

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Abstract

A substrate for α-l-idopyranosyluronic acid 2-sulfate 2-sulfohydrolase (iduronate sulfatase), the enzyme deficient in the Hunter syndrome, was prepared by deaminative cleavage of heparin and subsequent reduction of the disulfated disaccharide fragment with sodium borotritide, to give O-(α-l-idopyranosyluronic acid 2-sulfate)-(1→4)-2,5-anhydro-d-[³H-1]mannitol 6-sulfate. Incubation of this compound with enzyme gave a monosulfated radioactive product, which can be separated from the substrate by paper chromatography or electrophoresis. The reaction follows Michaelis-Menten kinetics, with a K_M of 3mm. The phosphate ion is a potent inhibitor.

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Cited by (33)

Mucopolysaccharidosis type II (Hunter syndrome): Clinical and biochemical aspects of the disease and approaches to its diagnosis and treatment
2020, Advances in Carbohydrate Chemistry and Biochemistry
Citation Excerpt :
Substrate 10 is composed of a sulfated IdoA glycosidically linked to a sulfated anhydromannitol that has been labeled with tritium. Substrate 10 was obtained by sodium borotritide (NaB3H4) reduction of disaccharide 9, derived from the nitrous acid degradation of heparin.129 The principle of the assay is shown in Scheme 2.
Mucopolysaccharidosis type II (MPS II, Hunter syndrome) is a rare X-linked lysosomal storage disease caused by mutations of the gene encoding the lysosomal enzyme iduronate-2-sulfatase (IDS), the role of which is to hydrolytically remove O-linked sulfates from the two glycosaminoglycans (GAGs) heparan sulfate (HS) and dermatan sulfate (DS). HS and DS are linear, heterogeneous polysaccharides composed of repeating disaccharide subunits of l-iduronic acid (IdoA) or d-glucuronic acid, (1 → 4)-linked to d-glucosamine (for HS), or (1 → 3)-linked to 2-acetamido-2-deoxy-d-galactose (N-acetyl-d-galactosamine) (for DS). In healthy cells, IDS cleaves the sulfo group found at the C-2 position of terminal non-reducing end IdoA residues in HS and DS. The loss of IDS enzyme activity leads to progressive lysosomal storage of HS and DS in tissues and organs such as the brain, liver, spleen, heart, bone, joints and airways. Consequently, this leads to the phenotypic features characteristic of the disease. This review provides an overview of the disease profile and clinical manifestation, with a particular focus on the biochemical basis of the disease and chemical approaches to the development of new diagnostics, as well as discussing current treatment options and emerging new therapies.
Clinical and metabolic aspects of sulfohydrolases in man
1987, Advances in Clinical Chemistry
This chapter presents a cumulative overview of the properties and role of sulfohydrolases and stimulates further studies on the enzymology and treatment of human genetic disorders caused by deficiencies of the sulfohydrolases. Mammals produce and excrete arylsulfates as a part of their detoxification mechanisms against phenolic compounds. Aryl-sulfate sulfohydrolases have been classified on the basis of their cellular location, substrate specificities, physicochemical properties, and the effect of certain reagents on the enzymatic reaction constants. Arylsulfohydrolase A forms an enzymatically active insoluble complex with a plant lectin, concanavalin A, at a high salt concentration, where electrostatic interactions are minimal. This insoluble complex is isolated by centrifugation. The chapter discusses the enzymatic aspects of diseases associated with the abnormal activities of sulfohydrolases. Metachromatic leukodystrophy is a human sphingolipidosis characterized by marked disintegration of the myelin sheath of the nerve cell and the accumulation of cerebroside 3-sulfate in brain, kidney, and other visceral organs.
Heparin trisaccharides with nonreducing 2-amino-2-deoxy-α-d-glucopyranosyl end-groups suitable as substrates for catabolic enzymes
1986, Carbohydrate Research
Heparin trisaccharides having the sequence O-(2-amino-2-deoxy-α-d-glucopyranosyl)-(1→4)-O-α-l-idopyranosyluronic acid-(1→4)-2,5-anhydro-d-[1-³H]mannitol have been prepared, as substrate models for studying sulfatases of heparan sulfate catabolism, by α-l-iduronidase cleavage of previously reported heparin tetrasaccharides, with additional chemical and enzymic modification as required. Three series are described, including isomeric sulfate esters of that trisaccharide with no N-substituent, with N-acetyl substitution, and with N-sulfate substitution. New features of the substrate specificity of the hydrolases used, including iduronate sulfatase, α-l-iduronidase, glucosamine 6-sulfate sulfatase, and heparin sulfamidase, were observed, and simple procedures for partial purification of these hydrolases are reported. The structures assigned to the trisaccharides are supported by the mode of preparation, reactions, regularities in electrophoretic behavior, and identities of the products of deamination.
Structural studies on heparin. Tetrasaccharides obtained by heparinase degradation
1984, Carbohydrate Research
Three tetrasaccharides representing major structural sequences of heparin were isolated in good yield and characterized after degradation of heparin by purified flavobacterial heparinase. N-Desulfation was necessary to achieve good separation of these closely related compounds from each other. One of the tetrasaccharides was shown to be derived from the fully sulfated repeating segments; to contain l-iduronic acid and six sulfate groups, and have the structure Δ_4,5-HexpA-(2-SO₄)-(1→4)-α-d-GlcpN-(N-SO₄)-(6-SO₄)-(1→4)-α-l-IdopA-(2-SO₄)-(1→4)-d-GlcN- (N-SO₄)-(6-SO₄). The second contained a d-glucuronic acid unit that was nonsulfated instead of the l-iduronic acid, and the third, obtained in a fairly low yield, contained five sulfate groups, three of which being located on the disaccharide at the nonreducing end, and having the structure Δ_4,5-HexpA-(2-SO₄)-(1→4)-α-d-GlcpN-(N-SO₄)-(6-SO₄)-(1→4)-α-l-IdopA-(2-SO₄)-(1→4)-d-GlcN- (N-SO₄). All tetrasaccharides had a sulfated, unsaturated uronic acid unit at the nonreducing end, confirming that the heparinase requires sulfated l-iduronic acid units for activity.
Selective depolymerisation of dermatan sulfate: Production of radiolabelled substrates for α-l-iduronidase, sulfoiduronate sulfatase, and β-d-glucuronidase
1983, Carbohydrate Research
Radiolabelled disaccharide substrates for α-l-iduronidase, β-d-glucuronidase, and sulfoiduronate sulfatase have been prepared from dermatan sulfate by application in sequence of N-deacetylation, deaminative cleavage, and reduction with NaBT₄. The yield of disaccharides was ∼87% of the total oligosaccharide fraction. Five disaccharides were isolated and tentatively identified. The major disaccharide, O-(α-l-idopyranosyluronic acid)-(1→3)-2,5-anhydro-d-[1-³H]talitol 4-sulfate (IdoA-anT4S), represented ∼75% of the total disaccharide fraction. The other disaccharides were O-(α-l-idopyranosyluronic acid 2-sulfate)-(1→3)-2,5-anhydro-d-[1-³H]talitol 4-sulfate (IdoA2S-anT4S), O-(β-d-glucopyranosyluronic acid)-(1→3)-2,5-anhydro-d-[1-³H]talitol 4-sulfate (GlcA-anT4S), O-(β-d-glucopyranosyluronic acid)-(1→3)-2,5-anhydro-d-[1-³H]talitol 6-sulfate (GlcA-anT6S), and O-(α-l-idopyranosyluronic acid)-(1→3)-2,5-anhydro-d-[1-³H]talitol (IdoA-anT), which represented ∼4.5, 11.2, 1.0, and 1.8%, respectively, of the total disaccharide fraction. When incubated with cultured skin-fibroblasts from normal controls, IdoA-anT4S was shown to be a sensitive substrate for α-l-iduronidase to produce 2,5-anhydro-d-talitol 4-sulfate (anT4S). Activity toward IdoA-anT4S was not observed with fibroblast homogenates from α-l-iduronidase-deficient patients (Mucopolysaccharidosis Type I). Similarly, normal-fibroblast homogenates degraded GlcA-anT6S to anT6S, and GlcA-anT4S to anT4S, at a rate 6 to 8 times greater than found for fibroblasts from β-d-glucuronidase-deficient patients (Mucopolysaccharidosis Type VII). IdoA-anT4S was hydrolysed by α-l-iduronidase at a rate 365 times greater than that for IdoA-anT. Sulfation of the anhydro-d-[1-³H]talitol residues is an important structural determinant in the mechanism of action of α-l-iduronidase on disaccharide substrates. IdoA2S-anT4S was degraded to IdoA-anT4S and then to anT4S by normal-fibroblast homogenates, whereas fibroblasts from α-l-iduronidase-deficient and sulfoiduronate sulfatase-deficient (Mucopolysaccharidosis Type II) patients produced considerably decreased levels of anT4s and IdoA-anT4S (and anT4S), respectively.
Activities of sulfatases for the degradation of acidic glycosaminoglycans in cultured skin fibroblasts from two siblings with multiple sulfatase deficiency
1983, Clinica Chimica Acta
Cultured skin fibroblasts from two siblings with multiple sulfatase deficiency (MSD) were assayed for the activities of sulfatases known to degrade acidic glycosaminoglycans (AGAG). There were iduronate sulfatase, arylsulfatase B, heparan sulfate (HS) sulfatase, N-acetylgalactosamine-6-sulfate sulfatase, HS-derived N-acetylglucosamine-6-sulfate sulfatase, and two keratan sulfate (KS)-derived N-acetylglucosamine-6-sulfate sulfatases.
The activities of sulfatases required for the degradation of HS were reduced to a greater extent than those for the degradation of dermatan sulfate (DS), and those of sulfatases associated with basic defect of Morquio disease type A were moderately decreased or normal. On the other hand, urinary excretion of AGAG in both patients was increased about 10-fold compared to controls, and especially, the excretion of HS and DS was increased about 150-fold and 50-fold, respectively. Keratan sulfate was not detected.
The results suggest that in patients with MSD the degradation of HS might be affected to a greater extent than that of DS.

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¹: Present address: Department of Human Genetics, Hadassah University Hospital, Jerusalem, Israel.

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An assay for iduronate sulfatase (hunter corrective factor)

Abstract

Biochem. Biophys. Res. Commun.

J. Biol. Chem.

Biochem. Biophys. Res. Commun.

J. Biol. Chem.

J. Biol. Chem.

Anal. Biochem.

J. Biol. Chem.

Carbohyd. Res.

Anal. Biochem.