Answer:
b. reducing molecules
Explanation:
Nicotinamide adenine dinucleotide (abbreviated NAD +, and also called diphosphopyridine nucleotide and Coenzyme I), is a coenzyme found in all living cells. The compound is a dinucleotide, as it consists of two nucleotides linked through their phosphate groups with a nucleotide that contains an adenosine ring and the other that contains nicotinamide.
In metabolism, NAD + participates in redox reactions (oxidoreduction), carrying electrons from one reaction to another.
Coenzyme, therefore, is found in two forms in cells: NAD + and NADH. NAD +, which is an oxidizing agent, accepts electrons from other molecules and becomes reduced, forming NADH, which can then be used as a reducing agent to donate electrons. These electron transfer reactions are the main function of NAD +. However, it is also used in other cellular processes, especially as a substrate for enzymes that add or remove chemical groups of proteins, in post-translational modifications. Due to the importance of these functions, the enzymes involved in the metabolism of NAD + are targets for drug discovery.