• 1 January 1983
    • journal article
    • research article
    • Vol. 21  (1) , 3-10
Abstract
The analogs [D-Abu2-Lys7]-phalloin (1) [Abu = .alpha.-aminobutyric acid] and [D-Ala2-Leu7]-phalloin (2) are obtained by cyclization of the monocyclic thioether peptides 2-mercapto-L-tryptophyl-L-(.epsilon.-Z)-lysyl-L-alanyl-D-.alpha.-aminobutyryl-L-cysteinyl-4-cis-hydroxy-L-prolyl-L-alanine cyclic (1 .fwdarw. 5) sulfide and 2-mercapto-L-tryptophyl-L-leucyl-L-alanyl-D-alanyl-L-cysteinyl-4-cis-hydroxy-L-prolyl-L-alanine cyclic (1 .fwdarw. 5) sulfide with dicyclohexylcarbodiimide and diphenylphosphoro-azidate, respectively. Analog 1 binds to F-actin with an association constant of 1.3 .times. 10-6 M whereas analog 2 exhibits practically no affinity. By reaction of 1 with tetramethyl-rhodaminyl-isothiocyanate a fluorescent derivative, rhodaminyl-lysine-phallotoxin, is obtained as a novel fluorescent probe for the visualization of F-actin in cell preparations.