1.1.3.42 solanapyrone synthase activity is rather unstable in both crude and partially purified states. It loses 55% of its activity after 36 h at 4°C but the addition of 30% glycerol markedly improves stability, the preparation retains 55% activity for 9 days at 4°C. Other additives such as EDTA, thiol reagents and reducing agents are not effective 714292