| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1986: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1985: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
JSTX which specifically blocked the excitatory postsynaptic potential and glutamate induced potential in crustacean neuromuscular synapses was purified about 300-fold from the venom glands of Nephila clavata by means of column chromatography on Sephadex G-10, CM-Sephadex C-25 and ODS HPLC. Characterization of the purified JSTX we found that the molecular weight was 566 and 2,4-dihydroxyphenylacetic acid, aspartic acid, cadaverine and one unknown component (may be a derivative of lysine) were detected in the acid-hydrolysate. The structure of JSTX was deduced to be Lysine-cadaverine-aspartic acid (asparagine)-2,4-dihydroxyphenylacetic acid.
JSTX was shown to inhibit L-glutamate binding to rat brain synaptic membranes in a dose-dependent manner. 2,4-Dihydroxyphenylacetic acid, a common moiety of spider toxins also inhibited specifically L-glutamate binging at a concentration similar to that of the toxin. In addition, the binding activity inhibited by 2,4-dihydroxyphenylacetic acid or JSTX was recovered by the addition of ferric ion. These results suggest that 2,4-dihydroxyphenylacetic acid is a functional part in the molecule of the toxins and the biological action of spider toxin is explained by the direct interaction to Fe-S center which is known to play an important role for the glutamate binding.
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