Comparative kinetic analysis of ascorbate (Vitamin-C) recycling dehydroascorbate reductases from plants and humans.

Ascorbate is an important cellular antioxidant that gets readily oxidized to dehydroascorbate (DHA). Recycling of DHA is therefore paramount in the maintenance of cellular homeostasis and preventing oxidative stress. Dehydroascorbate reductases (DHARs), in conjunction with glutathione (GSH), carry out this vital process in eukaryotes, among which plant DHARs have garnered considerable attention.

Structural and functional insights into the catalytic inactivity of the major fraction of buffalo milk xanthine oxidoreductase.

Background: Xanthine oxidoreductase (XOR) existing in two interconvertible forms, xanthine dehydrogenase (XDH) and xanthine oxidase (XO), catabolises xanthine to uric acid that is further broken down to antioxidative agent allantoin. XOR also produces free radicals serving as second messenger and microbicidal agent. Large variation in the XO activity has been observed among various species.