GAS-LIQUID-CHROMATOGRAPHY MASS-SPECTROMETRY ANALYSIS OF ANTICOAGULANT ACTIVE CURDLAN SULFATES

To evaluate the sulfation pattern of anticoagulant active curdlan sulfates, a methylation method, based on the synthesis of alkylated alditol acetates, followed by GLC-MS examination, was developed. By the specific cleavage of the sulfate esters, using solvolysis and the substitution of these liberated OH groups with ethyl iodide, a third kind of substitution was introduced in the alkylated alditol acetates, specifically replacing the former sulfate esters. The primary OH group in position 6 had more than the 10-fold accessibility to sulfation, in comparison to the secondary OH groups in positions 2 and 4. Products with a low DS were fairly homogeneously substituted, having unsubstituted or selectively C6-sulfated glucose units. Increasing DS was associated with a loss of homogeneity as well as selectivity of the C6 sulfation. Sulfation of C6-protected curdlan resulted in products with a higher content of sulfate groups in positions 2 and 4, and consequently a uniform charge distribution around the glucose monomer. Besides the dependence on the DS and the MW, also the sulfation pattern influenced the anticoagulant activity. The higher the portion of the secondary linked sulfate esters, the higher the anticoagulant activity. The C6-protected curdlan sulfates had activities normally corresponding to higher DS and MW.