TY - JOUR
T1 - Selective depolymerisation of dermatan sulfate
T2 - Production of radiolabelled substrates for α-l-iduronidase, sulfoiduronate sulfatase, and β-d-glucuronidase
AU - Hopwood, John J.
AU - Muller, Vivienne J.
N1 - Funding Information:
This work was supported by grants from the Research Trust of the Adelaide Children’s Hospital Inc. and the National Health and Medical Research Council of Australia.
PY - 1983/10/28
Y1 - 1983/10/28
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=0021114471&partnerID=8YFLogxK
U2 - 10.1016/0008-6215(83)88334-7
DO - 10.1016/0008-6215(83)88334-7
M3 - Article
C2 - 6423280
AN - SCOPUS:0021114471
SN - 0008-6215
VL - 122
SP - 227
EP - 239
JO - Carbohydrate Research
JF - Carbohydrate Research
IS - 2
ER -