Activation of heparin cofactor II by dermatan sulfate.

D M Tollefsen,C A Pestka,W J Monafo

doi:10.1016/s0021-9258(18)32276-2

Abstract

We have tested the ability of various glycosaminoglycans to increase the rate of inhibition of thrombin by heparin cofactor II (HCII) and by antithrombin III (ATIII) isolated from human plasma. Heparin, dermatan sulfate, and heparan sulfate from bovine liver (in order of decreasing activity) activated HCII. In contrast, only heparin and bovine liver heparan sulfate activated ATIII, whereas dermatan sulfate was inactive at concentrations less than or equal to 1 mg/ml. Heparan sulfate from human aorta, chondroitin 4-sulfate, chondroitin 6-sulfate, keratan sulfate, and hyaluronic acid had little or no activity with either HCII or ATIII. The second order rate constant for the thrombin-HCII reaction reached a maximum value of 6.4 X 10(8) M-1 min-1 in the presence of 250-500 micrograms/ml of dermatan sulfate compared to 3.8 X 10(8) M-1 min-1 in the presence of 40-80 micrograms/ml of heparin. When 125I-thrombin was incubated with plasma in the presence of greater than or equal to 100 micrograms/ml of dermatan sulfate, the protease became complexed exclusively with HCII, suggesting that HCII is the only thrombin inhibitor in human plasma that can be activated by dermatan sulfate.

Highlights

W e have tested the ability of various glycosaminoglycans to increase the rate of inhibition of thrombin by heparin cofactor I1 (HCII) and by antithrombin I11 (ATIII) isolated from human plasma
Glycosaminoglycans-Heparin from porcine intestinal mucosa, dermatan sulfate from porcine skin, chondroitin4-sulfate from whale cartilage,chondroitin6-sulfate from shark cartilage, hyaluronic acid from human umbilical cord, and keratan sulfate from bovine cornea were obtained from Sigma
This finding is consistent with previous experiments inwhich we demonstrated that alimiting amount of '*'I-thrornbin added directly to plasma becomes complexed preferentially with HCII a t concentrations of heparin >5 units/ml [8]

Summary

THEJOURNAOLF BIOLOGICACLHEMISTRY

Heparin accelerates inhibition of thrombin by both HCII and ATIII approximately 1000-fold [4, 6]. Heparin is a potent anticoagulant at a concentration of -1 Fg/ml, Teien et al [7] demonstrated that heparan sulfateanddermatansulfatealso prolonged theactivated partial thromboplastin timewhen added to human plasmaat higher concentrations. W e have tested the ability of various glycosaminoglycans to increase the rate of inhibition of thrombin by heparin cofactor I1 (HCII) and by antithrombin I11 (ATIII) isolated from human plasma. Dermatan sulfate, and heparan sulfate from bovine liver (in order of decreasing activity) activated HCII. Dermatan sulfate had no effect on the rate of protease inhibition by ATIII. We present evidence that the anticoagulant effect of dermatan sulfate is mediated by HCII. Trast, only heparin and bovine liver heparan sulfate activated ATIII, whereas dermatan sulfate was inac-

EXPERIMENTAL PROCEDURES

RESULTS

Keratan sulfate

Findings

DISCUSSION