Effect of oversulphated chondroitin and dermatan sulphate upon thrombin and factor Xa inactivation by antithrombin III or heparin cofactor II

Abstract

The kinetics of inhibition of human thrombin and Factor Xa by antithrombin III or heparin cofactor II were examined under pseudo-first-order conditions as a function of the concentration of naturally occurring oversulphated chondroitin and dermatan sulphates. The sulphated glycosaminoglycans (GAGs) studied were chondroitin sulphate D (CSD) (GlcA-2-SO4-GalNAc-6-SO4), chondroitin sulphate K (CSK) (GlcA-3-SO4-GalNAc-4-SO4), chondroitin sulphate H (CSH) (IdA-GalNAc-4,6-diSO4) and polysulphated dermatan sulphate (DPS) (IdA-2-SO4 or -3-SO4-GalNAc-4,6-diSO4). The data for the antithrombin III inhibition of thrombin showed a low degree of maximal potentiation of this interaction (congruent to 10-fold), which would appear to be characteristic of GAGs devoid of the high-affinity antithrombin III binding site. In contrast there was a greater potentiation of the inhibition of thrombin by heparin cofactor II with DPS showing an activity comparable to heparin in this interaction at a concentration two orders of magnitude lower than dermatan sulphate. DPS potentiated antithrombin III-Factor Xa interaction by 1200-fold, similar to that shown by high-affinity heparin of 6 kDa. The antithrombin III-Factor Xa interaction was potentiated by all other GAGs studied to a degree similar to that of heparin pentasaccharide with high affinity for antithrombin III. The findings suggest more stringent structural requirements for GAG stimulation of antithrombin-thrombin interaction than for antithrombin-Factor Xa or heparin cofactor-thrombin interaction, which may also be of significance in physiological control of haemostasis.

Heparan sulphate with no affinity for antithrombin III and the control of haemostasis

“…None of the GAGS, apart from the HA heparan sulphate, caused significant acceleration of the thrombin : ATIII interaction (< 30-fold maximum acceleration) as we have previously observed for non-heparin GAGS [16]. However, all caused inhibition of the rate of interaction between thrombin and ATII1 occurring in the presence of heparin ( fig.2).…”

“…The change in absorbance was followed at timed intervals in an Abbott bichromatic analyzer using 380/450 nm filter and first-order rate constants calculated from semilogarithmic plots of absorbance against time, as described previously [16].…”

A Unique Dermatan Sulfate-like Glycosaminoglycan from Ascidian:

“…The dependence of dermatan sulfate affinity for heparin cofactor II on sulfation of the iduronate residues has now been well established (41), but the importance of the sulfate group at the 4-position of the galactosamine units has not been explored as fully. Comparison of the activities of polysaccharides resembling dermatan sulfate extracted from hagfish demonstrate that sulfation at both the 4-and 6-positions of the galactosamine units does not confer heparin cofactor II affinity unless the iduronate residue is also sulfated (46). Our observation on the anticoagulant activity of the ascidian dermatan sulfate suggests that the particular disposition in space of the sulfate groups at the 2-position of ␣-L-iduronic acid and 4-position of the N-acetyl-␤-D-galactosamine residues is recognized by heparin cofactor II.…”

Altered Dermatan Sulfate Structure and Reduced Heparin Cofactor II-stimulating Activity of Biglycan and Decorin from Human Atherosclerotic Plaque

“…Highly charged DS preparations enriched in iduronic acid and the disulfated disaccharides have been shown to have the greatest activity. A high affinity hexasaccharide composed of the repeating disaccharide iduronic acid 2-sulfate 3 Nacetylgalactosamine 4-sulfate has been identified in porcine DS (20), and ⌬Di-4,6diS has been found to contribute to the activity expressed by ⌬Di-2,4S-enriched sequences (44,47). Iduronic acid seems to be important in that it can be sulfated at the C-2 position, while its epimer glucuronic acid is rarely sulfated.…”