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Table 1: Some enzymes important in metabolism

      Coenzyme         Abbreviation       Vitamin      Reaction in coenzyme
                            NAD      associated with            function
* Nicotinamide             NADP
 adenine dinucleotide                     activity     Transfer of hydrogen
* Nicotinamide          acetyl CoA   Nicotinamide      (electrons)
 adenine dinucleotide                                  Transfer of hydrogen
 phosphate                           Nicotinamide      (electrons)
* Coenzyme A
                                     Pantothenic acid  Transfer of (2 carbon
                                                       atoms) acetyl group

1- Nicotinamide adenine dinucleotide NAD

NAD+ + 2H+ + 2e        NADH + H+
                       (reduced form)

NADP+ + 2H+ + 2e       NADPH + H+
                       (reduced form)

       Nicotinamide adenine dinucleotide NAD and Nicotinamide adenine
dinucleotide phosphate NADP contain two basic units each and are termed
dinucleotides. The electrons formed on the outer membrane of the
mitochondrion are carried across to inner membrane by a coenzyme
NADP. They play a key role in energy metabolism by accepting and
donating electrons.

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