Schetinger M R, Falquembach F, Michelot F, Mezzomo A, Rocha J B
Department of Chemistry, Natural and Exact Sciences Center, Federal University of Santa Maria, RS, Brazil.
Neurochem Int. 1998 Sep;33(3):243-9. doi: 10.1016/s0197-0186(98)00024-2.
The modulatory effect of heparin and dextran sulfate 500,000 (sulfated polysaccharides) was studied on ATPDase and 5'-nucleotidase activities. These enzymes participate in the degradation of ATP and adenosine production at the synaptic cleft level. Nucleotide hydrolysis was inhibited by heparin and dextran sulfate 500,000. For ADP, the inhibition was more evident at low cation concentrations (0.15 mM Ca2+ or Mg2+), reaching a maximum of 75%. For ATP, the inhibitory effect was less prominent and independent of divalent cation concentration, reaching a maximum of 25%. For AMP, the inhibition observed was similar with either relatively high (1 mM) or with low Mg2+ concentrations tested (0.1 mM) and reached a maximum of 35%. K+ did not change the inhibitory potency of sulfated polysaccharide suggesting that its effects were not exclusively related to charge interaction. These results suggest that heparin and possibly other naturally occurring sulfated polysaccharides may have a potential role as modulator of extracellular nucleotide hydrolysis in the synaptic cleft region.
研究了肝素和硫酸葡聚糖500,000（硫酸化多糖）对ATP酶和5'-核苷酸酶活性的调节作用。这些酶参与突触间隙水平的ATP降解和腺苷生成。核苷酸水解受到肝素和硫酸葡聚糖500,000的抑制。对于ADP，在低阳离子浓度（0.15 mM Ca2+或Mg2+）下抑制作用更明显，最大可达75%。对于ATP，抑制作用不太显著且与二价阳离子浓度无关，最大可达25%。对于AMP，在相对较高（1 mM）或测试的低Mg2+浓度（0.1 mM）下观察到的抑制作用相似，最大可达35%。K+并未改变硫酸化多糖的抑制效力，表明其作用并非仅与电荷相互作用有关。这些结果表明，肝素以及可能其他天然存在的硫酸化多糖可能在突触间隙区域作为细胞外核苷酸水解的调节剂具有潜在作用。
