Editing Dehydrogenase (section)

=== NADP<sup>+</sup> ===
[[Nicotinamide adenine dinucleotide phosphate|NADP<sup>+</sup>]] differs from NAD<sup>+</sup> only in the addition of a phosphate group to the adenosine 5-membered carbon ring.  The addition of the phosphate does not alter the electron transport abilities of the carrier. The phosphate group creates enough contrast between the two groups that they bind to the active site of different enzymes, generally catalyzing different types of reactions.<ref name=":5" /><ref name=":6">{{Cite web|url=http://watcut.uwaterloo.ca/webnotes/Metabolism/hmsNadphRole.html|title=The physiological role of NADPH|website=watcut.uwaterloo.ca|access-date=2016-03-06|archive-date=2016-03-06|archive-url=https://web.archive.org/web/20160306193914/http://watcut.uwaterloo.ca/webnotes/Metabolism/hmsNadphRole.html|url-status=dead}}</ref>

These two electron carriers are easily distinguished by enzymes and participate in very different reactions.  NADP<sup>+</sup> mainly functions with enzymes that catalyze anabolic, or biosynthetic, pathways.<ref name=":6" /> Specifically, NADPH will act as a reducing agent in these reactions, resulting in NADP<sup>+</sup>. These are pathways that convert substrates to more complicated products, using ATP. The reasoning behind having two separate electron carriers for anabolic and catabolic pathways relates to regulation of metabolism.<ref name=":0" />
The ratio of NADP<sup>+</sup> to NADPH in the cell is kept rather low, so that NADPH is readily available as a reducing agent; it is more commonly used as a reducing agent than NADP<sup>+</sup> is used as an oxidizing agent.<ref name=":5" />