Ethylene formation from 1-aminocyclopropane-1-carboxylic acid by microsomal membranes from senescing carnation
S Mayak1, R L Legge, J E Thompson
1Department of Biology, University of Waterloo, N2L 3G1, Waterloo, Ont., Canada.
Abstract:
Isolated membranes from the petals of senescing carnation flowers (Dianthus caryophyllus L. cv. White-Sim) catalyze the conversion of 1-aminocyclopropane-1-carboxylic acid (ACC) to ethylene. A microsomal membrane fraction obtained by centrifugation at 131,000 g for 1 h proved to be more active than the membrane pellet isolated by centrifugation at 10,000 g for 20 min. The ethylene-producing activity of the microsomal membranes is oxygen-dependent, heat-denaturable, sensitive to n-propyl gallate, and saturable with ACC. Corresponding cytosol fractions from the petals are incapable of converting ACC to ethylene. Moreover, the addition of soluble fraction back to the membrane fraction strongly inhibits the ACC to ethylene conversion activity of the membranes. The efficiency with which isolated membranes convert ACC to ethylene is lower than that exhibited by intact flowers based on the relative yield of membranes per flower. This may be due to the presence of the endogenous soluble inhibitor of the reaction, for residual soluble fraction inevitably remains trapped in membrane vesicles isolated from a homogenate.
Related Concept Videos
Preparation of 1° Amines: Hofmann and Curtius Rearrangement Mechanism
Loss of Carboxy Group as CO2: Decarboxylation of Malonic Acid Derivatives
Aldehydes and Ketones with Amines: Enamine Formation Mechanism
Aldehydes and Ketones with HCN: Cyanohydrin Formation Mechanism
Carboxylic Acids to Esters: Acid-Catalyzed (Fischer) Esterification Mechanism
Aldehydes and Ketones with HCN: Cyanohydrin Formation Overview


