Purification and Some Properties of Alcohol Acetyltransferase from Banana Fruit

Abstract

Isoamyl acetate, one of the major characteristic aroma compounds of banana fruit (Musa sapientum L.), was synthesized by the condensation of acetyl-CoA and isoamyl alcohol under the action of alcohol acetyltransferase, which was found to be localized in the soluble fraction of pulp cells. The activity of this enzyme increased with the ripening of banana fruit. The enzyme was purified about 62-fold. The purified enzyme was very labile at pHs lower than pH 7.0 but relatively stable at pH 7.5˜9. The enzyme was most active at 30°C and pH 8.5. The molecular weight was estimated to be about 40,000 by gel filtration. Its Km values for acetyl-CoA and isoamyl alcohol were 50 μM and 0.4 mM, respectively.