Distribution of an enzyme system producing cis-3-hexenal and n-hexanal from linolenic and linoleic acids in some plants

The activity of the enzyme system (E₂-I) producing C₆-aldehydes from C₁₈-unsaturated fatty acids was investigated using about 40 plants. Green leaves of dicotyledonous plants belonging to the Sphenopsida, Pteropsida Theaceae and Leguminosae showed a high enzyme (E₂-I) activity but edible leafy vegetables and fuits and monocotyledonous plants showed a low activity. Seasonal changes in the enzyme (E₂-I) activities were observed. The concentrations of cis-3-hexenol (leaf alcohol) and trans-2-hexenal (leaf aldehyde) and the enzyme (E₂-I) activities showed a correlation; high concentrations were observed in the summer but they were low in the winter.