J. Biol. Chem., Vol. 260, Issue 16, 9146-9149, 08, 1985
A sulfatase specific for glucuronic acid 2-sulfate residues in glycosaminoglycans
PN Shaklee, JH Glaser and HE Conrad
Although 2-O-sulfated L-iduronic acid (IdoA) residues have been known to
occur in heparin, 2-O-sulfated D-glucuronic acid (GlcA) residues have been
reported only recently (Bienkowski, M. J., and Conrad, H. E. (1985) J.
Biol. Chem. 250, 356-365). Disaccharides prepared by cleavage of heparin
and N-deacetylated chondroitin 6-sulfate with nitrous acid were used to
demonstrate a new sulfatase that catalyzed the removal of the 2-O-sulfate
substituents from GlcA but not IdoA residues. The deamination products were
labeled by NaB3H4 reduction to give disaccharides from heparin and
chondroitin sulfate which had reducing terminal 2,5-anhydro-D-mannitol
([3H]AManR) and 2,5-anhydro-D-talitol ([3H]ATalR) residues, respectively.
IdoA(2-SO4)-[3H]AManR(6-SO4) from heparin and GlcA(2-SO4)-[3H]ATalR(6-SO4)
from chondroitin sulfate were purified for use as substrates.
GlcA(2-SO4)-[3H]AManR(6-SO4) was prepared by epimerization of
IdoA(2-SO4)-[3H]AManR(6-SO4) with hydrazine at 100 degrees C. Lysosomal
enzyme preparations from chick embryo chondrocytes and from two normal
human fibroblast cell lines catalyzed the removal of the 2-O-SO4
substituent from the uronic acid residues of IdoA(2-SO4)-[3H]AManR(6-SO4),
GlcA(2-SO4)-[3H] AManR(6- SO4), and GlcA(2-SO4)-[3H]ATalR(6-SO4). In
contrast, a lysosomal enzyme preparation from a human fibroblast cell line
deficient in idurono-2- sulfatase (Hunter's-syndrome), which had no
activity on the IdoA(2-SO4)- [3H]AManR(6-SO4), converted
GlcA(2-SO4)-[3H]AManR(6-SO4) to a mixture of GlcA-[3H] AManR(6-SO4) and
[3H]AManR(6-SO4). This enzyme also converted GlcA(2-SO4)-[3H]ATalR(6-SO4)
to a mixture of GlcA-[3H]ATalR(6- SO4) and [3H]ATalR(6-SO4). Digestion of
both GlcA(2-SO4)-[3H]AManR(6- SO4) and GlcA(2-SO4)-[3H]ATalR(6-SO4) was
inhibited by 35SO2-4 and was arrested at the monosulfated disaccharide
stage by 1,4-saccharolactone. The glucurono-2-sulfatase exhibited a pH
optimum of 4. The results indicate that there exists a separate sulfatase
for the removal of sulfate substituents from C-2 of GlcA residues in
glycosaminoglycans.