Inhibitor of 1-aminocyclopropane-1-carboxylate (ACC) synthase; applied to apples, pears, stone fruits, and walnuts to inhibit ethylene production and delay ripening. Amino acid antimetabolite produced by fermentation of Streptomyces. Prepn: J. Berger et al., US 3751459 (1973 to Hoffmann-La Roche); D. L. Pruess et al., J. Antibiot. 27, 229 (1974) PubMed. Synthesis of dl-form: D. D. Keith et al., J. Org. Chem. 43, 3713 (1978) DOI. Crystal structure in complex with ACC synthase: G. Capitani et al., J. Biol. Chem. 277, 49735 (2002) DOI PubMed. Mechanism of action study: M. E. Saltveit, Postharvest Biol. Technol. 35, 183 (2005) DOI.