<prompt> All the following biochemical roles of the Ascorbic acid EXCEPTRole of coenzyme in hydroxylation of proline and lysineDeamination of the hydroxyl group containing amino acidsSteroid biosynthesisBile acid synthesis  <response>: Deamination of the hydroxyl group containing amino acids 134-U.S 3rd 165-Rana ShindeMetabolic roles and Functions of Ascorbic acid1. Role in cellular Oxidation-Reduction - serving as hydrogen-transport agent2. Role in collagen synthesis - Hydroxy proline and hydroxylysine are important constituents of mature collagen fibres. The are hydroxylated by corresponding hydroxylases in presence of vitamin C, Fe and molecular O23. Functional activity of FibroblastsOsteoblasts - formation of MPS of connective tissue, dentine and intercellular cement substance of capillaries.4. Role in Tryptophan metabolism - as a cofactor for hydroxylation of tryptophan to form 5-OH derivative in the pathway of biosynthesis of serotonin 5-HT5. Role in Tyrosine metabolism as a cofactor with the enzyme P-OH phenyl pyruvate hydroxylase, which is necessary for hydroxylation and conversion of P-OH phenyl pyruvate to Homogentisic acid Alkaptonuria6. Formation of Active FH4 Tetrahydrofolate - vitamin-C regulates the conversion of folic acid to folinic acid so-called citrovorum factor7. Formation of Ferritin; ATP, NAD and NADP stimulates the process.8. Absorption of Fe - helps in absorption of Fe in foods. hypochromic, microcytic anemia9. Role in electron transport system of mammalian microsomes10. Action on Certain Enzymes-ActivationInhibition - Arginase and papain are activated, whereas, activity of the enzymes like urease and b-amylase from plants is inhibited11. Role in formation of Catecholamines - as a coenzyme with the enzyme dopamine hydroxylase, which catalyzes the conversion of dopamine to norepinephrine12. Role in formation of Carnitine - Formation of carnitine in liver by hydroxylation by g-butyrobetain13. Role in a-oxidation of fatty acids helps in action of the enzyme a-hydroxylase a-mono-oxygenase14. Effect on cholesterol levels - Relation of ascorbic acid with hypocholesterolaemia in man and guinea pigs15. Role in stress The synthesis of bile acids from cholesterol enzyme-7 a-hydroxylase is enhanced by ascorbic acid 132-US16. Vitamin-C has also been reported to act as coenzyme for cathepsins and liver esterases17. Ascorbic acid in both leucocytes and platelets found to be lowered significantly in women taking OCP.18. Synthesis of corticosteroid hormone - Adrenal gland possess high levels of ascorbic acid, particularly in periods of stress. It is believed that vitamin C is necessary for the hydroxylation reaction in the synthesis of corticosteroid hormone 132-US19. Sparing action of other vitamins - vitamin C is strong anti-oxidant. It spares vitamin A, vitamin E, and some B-complex vitamins from oxidation20. Preventive action on cataract - vitamin C reduces the risk of cataract formation Deamination of the hydroxyl group containing aminoacid requires pyridoxalphosphate 