All aerobic organsims are exposed to reactive oxygen species (hydrogen peroxide superoxide radicals, hydroxyl radicals, etc.), which can damage vital biomolecules, such as DNA, lipids and proteins. In order to cope with this, the organisms protect themselves in different ways, and one important way is by low molecular weight antioxidants, which are often obtained from the diet. It has been shown that fruits and vegetables promote human health and antioxidants are supposed to play an important role. In this project the ability of antioxidants to protect important biomolecules is evaluated. Effects on DNA and its building blocks have been studied earlier in the project and during 2006 the work focused on protection of proteins, especially the enzyme chloroperoxidase. This is an enzyme that catalyses a wide range of interesting reactions, but its practical utility is limited by its poor operational stability. It was discovered that antioxidants efficiently protected the enzyme and thus prolonged its lifetime and increased the amounts of reaction products obtained. The most efficient antioxidant was caffeic acid, which is found in relatively large amounts in coffee.

Supervisor: Patrick Adlercreutz