Enzymatic ethylene formation from 1-aminocyclopropane-1-carboxylic acid by manganese, a protein fraction and a cofactor of etiolated pea shoots

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Abstract
The cofactor of enzymatic, 1-aminocyclopropane-1-carboxylic acid dependent ethylene formation was concentrated on cation exchange columns. When chelators of cations were added to the homogenates, cofactor activity was lost. Cofactor fractions were partly resistant to oxidation at 600° C. Mn2+ substituted for the cofactor in ethylene formation from 1-aminocyclopropane-1-carboxylic acid by a protein fraction isolated from etiolated pea shoots. In addition, Mn2+ enhanced the stimulatory effect of the concentrated cofactor. The elution volume for the cofactor on a Sephadex G-25 column was lower than that of MnCl2. In paper electrophoresis the cofactor migrated to the cathode at pH 10.8 and 2.2. The RF of cofactor on cellulose plates developed in butanol: acetic acid: H2O was 0.4. After cellulose chromatography, cofactor activity had to be reconstituted by the addition of MnCl2. Chelators, anti-oxidants, and catalase were inhibitors of Mn2+-cofactor-dependent ethylene formation. The protein necessary for 1-aminocyclopropane-1-carboxylic acid dependent ethylene formation in vitro was seperated from 95–98% of the total protein in homogenates by DE-52 cellulose chromatography and (NH4)2SO4-fractionation.