L-ascorbate peroxidase (AP) is a heme peroxidase. This group of enzyme catalyse the reduction of hydrogen peroxide (H2O2) to water and the concurrent oxidisation of a range of substrates, in this case ascorbic acid. Ascorbic acid is a strong antioxidant that is effective in scavenging superoxide (O2-'), hydroxyl (OH') radicals and singlet oxygen. It can also remove H2O2 in the following reaction.
AP is the main enzyme responsible for hydrogen peroxide removal in the chloroplasts and cytosol of higher plants.
Defined by 5 residues: ARG:A-37 [auth A-38]HIS:A-41 [auth A-42]HIS:A-162 [auth A-163]TRP:A-178 [auth A-179]ASP:A-207 [auth A-208]