Palytoxin induces K⁺ release from yeast cells expressing Na⁺, K⁺-ATPase.

Abstract

Palytoxin is unique in many respects (2). It is synthesized by corals (Palythoa caribaeorum) or by a therewith associated, unknown microorganism. It is the most toxic animal toxin, with an LD₅₀ (i.v.) of around 100 ng/kg in rabbits, mice, and guinea-pigs. It is a food poison for man because it occurs, perhaps secondarily, also in crabs. In contrast to most of the other animal toxins, it is not composed of typical amino acids, but of three sequential components connected by peptide links: namely, a polyhydroxy omega-amino acid of about 2500 Da, dehydro beta-alanine, and n-aminopropanol. Palytoxin forms pores of high selectivity for alkali ions in all mammalian cell membranes investigated so far. The resulting membrane depolarization promotes Ca²⁺ entry, which leads to contraction of smooth and striated muscles and to release of neurotransmitters from the brain.