Rat heparan sulphates. A study of the antithrombin-binding properties of heparan sulphate chains from rat adipose tissue, brain, carcase, heart, intestine, kidneys, liver, lungs, skin and spleen.

Adult male rats were given [35S]sulphate intraperitoneally. Heparan [35S]sulphate (HS) chains were recovered from adipose tissue, brain, carcase, heart, intestine, kidneys, liver, lungs, skin and spleen by digestion with Pronase, precipitation with cetylpyridinium chloride, digestion with chondroitin ABC lyase and DNAase and gradient elution from DEAE-Sephacel. Purity was confirmed by agarose-gel electrophoresis and degradation with HNO2. Fractionation by gradient elution from antithrombin-agarose indicated that the proportion of HS with high binding affinity for antithrombin (HA-HS) ranged from 4.7% (kidneys) to 21.5% (brain). On a mass basis the major sources of HA-HS were carcase, skin and intestine. HA-HS from intestine was arbitrarily divided into subfractions I-VI, with anticoagulant activities ranging from 1 to 60 units/mg [by amidolytic anti-(Factor IIa) assay] and from 4 to 98 units/mg [by amidolytic anti-(Factor Xa) assay], indicating that the antithrombin-binding-site densities of HA-HS chains covered a wide range, as shown previously for rat HA-heparin chains [Horner, Kusche, Lindahl & Peterson (1988) Biochem. J. 251, 141-145]. HA-HS subfractions II, IV and VI were mixed with samples of HA-[3H]heparin chains and rechromatographed on antithrombin-agarose. Affinity for matrix-bound antithrombin did not correlate with anticoagulant activity, e.g. HA-HS subfraction IV [38 anti-(Factor Xa) units/mg] was co-eluted with HA-heparin chains [127 anti-(Factor Xa) units/mg].