Synthesis of a [14C]-labelled photoactivatable cyclic tetrapeptide: [carbonyl-14C]-4-benzoylbenzoyl MeSer1-tentoxin

The synthesis of a new photochemical probe for labelling tentoxin 1 binding sites in the soluble part of chloroplast F0F1 ATPsynthase is described. [Carbonyl-14C]-4-benzoylbenzoyl MeSer1-tentoxin 6 was synthesised by coupling MeSer1-tentoxin 2 with [carbonyl-14C]-4-benzoylbenzoic acid 3, itself obtained by coupling [1-14C]-benzoyl chloride with the dilithio derivative of 4-bromobenzoic acid (9 ). Photolysis of the probe in methanolic solution occurs readily upon irradiation with UV light at 366 nm. Copyright © 2000 John Wiley & Sons, Ltd.