Achatin-I, an endogenous neuroexcitatory tetrapeptide from Achatina fulica Férussac containing a D-amino acid residue
Kamatani, Y.; Minakata, H.; Kenny, P.T.; Iwashita, T.; Watanabe, K.; Funase, K.; Sun, X.P.; Yongsiri, A.; Kim, K.H.; Novales-Li, P.
Biochemical and Biophysical Research Communications 160(3): 1015-1020
1989
ISSN/ISBN: 0006-291X PMID: 2597281 Document Number: 343539
A tetrapeptide named achatin-I was purified from the suboesophageal and cerebral ganglia of the African giant snail Achatina fulica Ferussac, and evoked a potent neuroexcitatory effect. The amino acid sequence of achatin-I is Gly-D-Phe-Ala-Asp. Achatin-I induced a voltage-dependent inward current, due to Na+, on the identifiable giant neuron, periodically oscillating neuron (PON), of the same snail. All possible isomers of achatin-I were synthesized using the solid-phase method. The sensitivity of the neuron to achatin-I and its isomers was strictly stereospecific; among the various isomers, only achatin-I showed marked effects (ED50 = 2.29 .times. 10-6 M), while Gly-D-Phe-D-Ala-Asp, the synthetic D-Ala-isomer, was less than 10-3 active.