1-O-trans-Cinnamoyl-β-ᴅ -glucopyranose: Alcohol Cinnamoyltransferase Activity in Fruits of Cape Gooseberry (Physalis peruviana L.)

Abstract

Methyl and ethyl cinnamate are aroma volatiles frequently occurring in fruits. Evidence was obtained that the enzymatic transfer of cinnamic acid to endogenous alcohols present in fruits (methanol, ethanol. 1-propanol) depended on energy-rich 1-O-glycosyl esters of cinnamic acid which served as acyl donor molecules. A putative l-O-trans-cinnamoyl-β-D-gluco-pyranose: alcohol cinnamoyltransferase from cape gooseberry (Physalis peruviana L.) was active towards l-O-trans-cinnamoyl-β-D-glucopyranose and l-O-trans-cinnamoyl-β-D-gentio-biose. The enzyme was purified 290-fold by a protocol including ammonium sulphate precipitation, solubilization by Triton X-100, gel permeation and affinity chromatography on conca-navalin A. The acidic glycoprotein (pI = 4.8) most probably is membrane bound. The distribution of alcohol cinnamoyltransferase activity in gel chromatography fractions suggests a native Mrof 75,000. For l-O-trans-cinnamoyl-β-D-glucopyranose, an apparent Kmof 69 was determined. At pH > 6.0, non-enzymatic transesterification superposes the enzymatic transformation.