Inhibition of mitochondrial respiration by asteltoxin, a respiratory toxin from Emericella variecolor.

Asteltoxin, a respiratory toxin from Emericella variecolor, was examined for an inhibitory effect on mitochondrial function. Asteltoxin strongly inhibited state 3 respiration, which was released by an uncoupling agent, 2,4-dinitrophenol (DNP), indicating that the action site of asteltoxin is localized in the energy transfer system of mitochondria. Asteltoxin strongly depressed Mg2+-ATPase activity in mitochondria and only slightly affected Na+, K+-activated ATPase in microsomes at the concentration range for inhibition of mitochondrial respiration.