Is Vitamin C Coenzyme
                            Vitamins and Coenzymes
        
                  Water - Soluble Vitamins
                                              - Vitamin B1 - thiamine          
                      - Converted to thiamine pyrophosphate coenzyme            
- Acts by nucleophilic attack on C = O            
- Permits C - C bond cleavage and formation            
          - Vitamin B2 - riboflavin          
                      - Incorperated in FMN (Flavin MonoNucleotide) and FAD (Flavin Adenine Dinucleotide) coenzymes            
- Acts in Redox Reactions            
- Can accept and donate 2 e-              and 2 H+            
          - Vitamin B6 - pyridoxal (-ol, -amine)          
                      - Converted to pyridoxal phosphate coenzyme            
- Acts by forming Schiff base with -NH                2                            of substrate            
- Permits cleavage of C - C, C - O, C - S, C - H, and C - N bonds in area of attachment            
- Very versatile, but amino group needed in substrate            
          - Vitamin B12 - cyanocobalamin          
                      - Coordination complex of Co+ in a corrin ring            
- Converted to 5'-deoxyadenosylcobalamin coenzyme            
- Acts to exchange -H and another group on adjacent C's            
- Transfers Methyl group from Me-THF to homocycteine to synthesize Met            
          - Nicotinamide (NIacin, nicotinic ACid vimintIN)          
                      - Converted to NAD and NADP coenzymes            
- Functions in Redox Reactions by accepting and donating 2e-              and 1 H+            
          - Pantothenic Acid          
                      - Converted to Phospho-form coenzyme            
- Activates Acyl moieties for condensation and enolization            
          - Biotin (vitamin H)          
                      - Coenzyme            
- Incorperates CO2              in              B              carboxylation reactions            
- "Binds the egg white glycoprotein avidin with Kd              = 10-15              M            
- Vitamins #5-7 are part of the B complex            
          - Vitamin C - ascorbic acid ("antiscorbutic") ("anti-scurvy")          
                      - involved in hydroxylation of proline in collagen, therefore important for wound healing            
- Prevent common cold? How?            
          - Folic Acid - pteroylglutamic acid          
                      - Converted to tetrahydrofolic acid (THF)            
- Carries C-1 groups at all oxidation levels            
- More properly considered a substrate than a coenzyme            
Non-Vitamin Coenzyme
                                              - Lipoic Acid          
                      - (Isolated in 1951 by Lester Reed at UT-Austin - he obtained 30mg from 10 tons of liver residue.)            
- Relays electrons and acetyl groups between catalytic subunits of pyruvate dehydrogenase complex.            
Lipid-Soluble Vitamins
                                              - Vitamin A - trans-retinol          
                      - Converted to visual pigment cis-retinal            
- (Also contributes to animal growth and development - How? Retinoic acid?)            
          - Vitamin D - 7-dehydrocholesterol          
                      - Converted to hormone 1,25-Dihydroxy vitamin D3            
- (Stimulates gene expression to regulate calcium metabolism)            
          - Vitamin E -            a-tocopherol          
                      - Antioxidant            
- Prevents sterility - in rats, How?            
          - Vitamin K - phylloquinone in plants; menaquinone in aminals and bacteria          
                      - Cofactor for formation of              gamma-carboxyglutamic acid in serine proteases of blood clotting cascade, and some other Ca++              binding proteins.            
-                , chelates Ca++ , chelates Ca++
- e.g. 1st 10 glu residues of prothrombin are converted to              gamma-carboxyglu, by addition of CO2.            
      Is Vitamin C Coenzyme
  Source: https://www.utdallas.edu/~rmarsh/ClassNotes/biochem/Biochem1/Vitamins%20and%20Coenzymes/Vitamins_and_Coenzymes.html