Mediterranean thistle

ATP out of and ADP into the mitochondrion. Translocation is inhibited by two well-known toxins, atractyloside and bongkrekic acid, the former a glucoside found in the Mediterranean thistle and the latter produced by a Pseudomonas bacterium. 

Diterpenes (C20) can be linear as in the phytol part of chlorophyll or mono- to tetracyclic.87 Very well researched are the tricyclic taxanes of which taxol A from the Taxus baccata tree inhibits cell division and has found use in anticancer treatment. Certain labdanes inhibit blood platelet aggregation and kaurane norditer-pene glycosyl ester atractylosides from the Mediterranean thistle block the ATP/ADP translocation - such diterpenes are very toxic when ingested. Ubiquitous plant-derived kaurane-type diterpenes are the plant hormones (gibberellins) or defense substances (phytoalexins). 

The movement of ATP out of the mitochondrial matrix and the movement of ADP back in to it from the cytoplasm are catalyzed by the same membrane protein, ATPiADP translocase. Inhibition of this transporter by the compoiuid atractyloside (from the Mediterranean thistle) prevents ADP from being available to the FiFoATPase. This causes ATP synthesis to stop, the proton gradient to stay high, and the proton pirnips to be inhibited by the enormous backpressiue of protons. Fuel oxidation will cease as will the ability for ATP to enter the cytoplasm. Thus the cytoplasmic ATP concentration will quickly fall. 

Atractyloside a glucoside from the Mediterranean thistle Atraclylis gummiiera. It is a competitive inhibitor of adenine nucleotide binding and transport across the inner mitochondrial membrane. The closely related carboxyatractylate binds with higher affinity (Kj 10 M) and is not displaced by adenine nucleotides. 

Atractyloside is a toxic glycoside from the rhizomes of the Mediterranean thistle Atractylis gummifera] it competes with ADP for binding to the carrier. 

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