Polarographic Investigation Op B-n-oxalyl-l-ab-diaminofr.ofrionic Acid A Neurotoxin Prom The Seeds Op Lathyrus Sativus(guaya)

Polarographic investigations of £-N-Oxalyl-L-a > 0-Diaminopropionicrnacid, ODAP, a neurotoxin from the seeds of Lathyrusrnsativus(Guaya) have been made.rnAqueous solutions of ODAP in KC1 supporting electrolyterngave a single polarographic wave with a half-wave potential ofrn-1 ,518V, This wave was found to be due to the irreversiblerndischarge of hydrogen. The reduction wave disappeared onrnstanding and may be due to intramolecular rearrangement leadingrnto lactone formation.rnAt more positive potential a second peak appears for pH’srnless than 2. The reduction wave shifts towards more positivernvalues as the pH decreases. This reduction wave could be due torna direct reduction of the protonated amino acid,rnPolarograms of qqueous solution of Cu(ll), Ni(ll ), Zn(ll),rnCd(ll), Pb(ll) and Co(ll) in KC1 supporting electrolyte were notrnaffected by the addition of ODAP, However, in ammonia bufferrn( pH = 8,2) and when ODAP was added only Ni(ll) and Co(ll) showedrnlarger shifts in the differential pulse polarographic peakrnpotentials after one day,rnPolarographic behavior of complexes of ODAP with Ni(ll) andrnCo(ll) in borax buffer (pH = 9.2) have been studied. The reductionrnof both complexes were polarographically irreversible.rnThe stability constant and ligand number of the Ni(ll)~ ODAPrncomplex in borax ( pH = 9 ,2) were determined. The simple andrncomplex metal ions were reduced irreversibly. The ligand numberrnwas determined to be 2 and the stability constant calculated tornbe log $= 7.4

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