Ethylene biosynthesis. 12. Analog approach to the active site topography of the ethylene-forming enzyme. Novel hydroxamate inhibitors

Article abstract of DOI:10.1021/jo00123a012

In order to understand both the substrate specificity and active site topography of the ethylene-forming enzyme (EFE), a number of analogs of its substrate, 1-aminocyclopropanecarboxylic acid, have been prepared and studied as inhibitors. Because of the dependence of EFE activity on iron, hydroxamic acids, a functional group known to bind iron tightly, derived from several small carboxylic/amino acids were studied along with the parent amino acids. The activity of these materials was assayed in vitro against the purified EFE from apple fruit. The varying potency of the amino acid hydroxamates suggests that they do not act simply by binding to iron and removing it from the enzyme. The order of their potency was consistent with the idea that binding reflects both metal chelation and hydrophobic interactions in the active site. The most potent inhibitor, ACC-hydroxamate, has about 1 μM K(i).