Xanthophyll cycle is a pathway that transforms zeaxanthin to violaxanthin and antheraxanthin through enzymes. Xanthophyll cycle mainly takes place in diatoms and dinoflagellates of plants in high-light condition. Zeaxanthin is obatined from zeaxanthin biosynthesis that transforms lycopene to zeaxanthin (indirectly). Zeaxanthin is catalyzed into antheraxanthin and antheraxanthin catalyzed into violaxanthin both by the enzyme, zeaxanthin epoxidase with cofactor FAD. Violaxanthin deepoxidase/antheraxanthin deepoxidase can reverse the above reactions (i.e. violaxanthin to antheraxanthin and antheraxanthin to zeaxanthin).
Xanthinuria Type II is a rare inborn error of metabolism (IEM) and autosomal recessive disorder and caused by a defective xanthine dehydrogenase. Xanthine dehydrogenase catalyzes the conversion of hypoxanthine into xanthine and conversion of xanthine into uric acid. This disorder is characterized by a large accumulation of xanthine and hypoxanthine; as well as dissipation of uric acid. Symptoms of the disorder include blood in the urine, recurrent urinary tract infections and abdominal pain. It is estimated that xanthinuria types I and II affects 1 in 69,000 individuals.
Xanthinuria Type II is a rare inborn error of metabolism (IEM) and autosomal recessive disorder and caused by a defective xanthine dehydrogenase. Xanthine dehydrogenase catalyzes the conversion of hypoxanthine into xanthine and conversion of xanthine into uric acid. This disorder is characterized by a large accumulation of xanthine and hypoxanthine; as well as dissipation of uric acid. Symptoms of the disorder include blood in the urine, recurrent urinary tract infections and abdominal pain. It is estimated that xanthinuria types I and II affects 1 in 69,000 individuals.
Xanthinuria Type II is a rare inborn error of metabolism (IEM) and autosomal recessive disorder and caused by a defective xanthine dehydrogenase. Xanthine dehydrogenase catalyzes the conversion of hypoxanthine into xanthine and conversion of xanthine into uric acid. This disorder is characterized by a large accumulation of xanthine and hypoxanthine; as well as dissipation of uric acid. Symptoms of the disorder include blood in the urine, recurrent urinary tract infections and abdominal pain. It is estimated that xanthinuria types I and II affects 1 in 69,000 individuals.
