All of the products of hydroperoxide lyase activity undergo further reactions. Alcohol dehydrogenase, for example, mediates the reduc- tion of Z3-hexenal and n-hexanal to Z 3-hexenol and n-hexanol, respectively, while 12-OXO-C9Z dodecenoic acid isomerizes to 12. OXO-(10E)- dodecenoic acid. Z3-hexanal also isomerizes with formation of E-2-hexenal and E-3-hexenal. Further reactions, often involving pyrrolysis auto-oxidation occur, especially during fir ing, resulting ultimately in formation of compounds, such as hexa noic acid, E-2-hexenoic acid and E-3-hexenoic acid(Figure 4.10)