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Coenzymes and Vitamins

Coenzymes and Vitamins. Jen Rozler Stephanie Mazziotta Whitney Tripp. What are Coenzymes and Cofactors?. Enzymes sometimes need assistance to catalyze reactions A small non-protein “helper” molecule is known as a cofactor. Examples of cofactors include Fe and Zn.

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Coenzymes and Vitamins

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  1. Coenzymes and Vitamins Jen Rozler Stephanie Mazziotta Whitney Tripp

  2. What are Coenzymes and Cofactors? • Enzymes sometimes need assistance to catalyze reactions • A small non-protein “helper” molecule is known as a cofactor. Examples of cofactors include Fe and Zn. • If a co-factor is organic, it is called a coenzyme • Coenzymes carry molecules or electrons. They are loosely bound to the enzyme they work with.

  3. Interesting facts about Coenzymes • An enzyme will be completely inactive without its required cofactor or coenzyme. • The inactive enzyme is called an apoenzyme. • Once the coenzyme is present and the enzyme has been activated, it is known as a holoenzyme.

  4. How do Coenzymes work? • All coenzymes transfer something (molecules, etc.) from one compound to another. • Some remain tightly bound to the enzyme during this process. • Others separate themselves from the enzyme, carrying the transported substance along with them. • Coenzymes are not specific to a particular enzyme; the same coenzyme can assist several different enzymes

  5. How do Coenzymes work cont. • Unlike cofactors, coenzymes are not attached to the enzyme they work with. • They attach themselves to the active site of the enzyme, right alongside the substrate. • The reaction involves both the coenzyme and the substrate, and they both leave the reaction changed in some manner.

  6. Examples of Coenzymes • Nicotinamide adenine dinucleotide, or NAD+. Carries reducing power. Derived from niacin. • Flavin adenine dinucleotide, or FAD. Also carries reducing power. Derived from riboflavin. • Coenzyme A. Involved in synthesizing and oxidizing fatty acids. Also oxidizes pyruvate during the citric acid cycle.

  7. Recycling Coenzymes

  8. Coenzymes play important roles in biochemical processes • Glycolysis, or the breakdown of glucose to form two molecules of pyruvate, is performed by all life forms. • Pyruvate is then oxidized by Coenzyme A to form Acetyl CoA.

  9. Coenzymes and biochemical processes, cont. • Acetyl CoA now enters the Krebs cycle. This cycle produces ATP • ATP is crucial to life; it transports chemical energy within cells and makes such processes as metabolism possible

  10. ATP and Coenzymes • ATP deserves some special attention here; not only is it crucial to life, but it is also formed through the action of a number of coenzymes. • NAD, NADP (nicotinamide adenine dinucleotide phosphate) and FAD carry electrons from one molecule to another. • Removal of electrons= oxidation • Addition of electrons= reduction

  11. ATP and Coenzymes, cont. • Oxidizing enzymes remove electrons from one substrate and pass them on to a coenzyme, which is now reduced. • The coenzyme then passes the electrons to a new substrate. In this case, the coenzyme becomes oxidized and is a reducing agent.

  12. Coenzymes and Vitamins • The majority of coenzymes are synthesized from vitamins. • Certain bacteria are able to create all their own vitamins and make them into the needed coenzymes • Humans, on the other hand, require their vitamins from external sources

  13. What is a Vitamin? • Vitamins- essential organic nutrients that: • Don’t provide energy • Required in small quantities • Americans consume vitamins that are: • Naturally present in foods • Added to foods by fortification • Supplied by supplements http://www.geninv.net/2009/07/health-benefits-of-vitamin-c-importance-of-vitamin-c/

  14. Vitamins on Food Labels • Vitamins added for two reasons: • Fortified (processed) foods • Government guidelines • Manufacturer’s selling points • Preserve foods • Using vitamin antioxidants • Required: Vitamin A and C • Ingredient Lists= supplements http://nutritionminute.blogspot.com/2011/04/fortified-foods.html http://new.brookshirebrothers.com/Products/OOrganics/CheeseDairy.aspx

  15. Fat-soluble vs. Water-soluble Water Fat Vitamin A Vitamin D Vitamin E Vitamin K • Thiamin (B1) • Riboflavin (B2) • Niacin (B3) • Pantothenic Acid • Biotin • B6 (Pyridoxal) • Folic Acid • B12 (Cyanocobalamin) • Vitamin C

  16. How are Vitamins lost? • Fat-solubles store better • Water-solubles lost in water ie. cooking • All vulnerable to degradation (heat, light, oxygen, time) and processing! • Some added back into processed foods (enrichment) http://www.dreamstime.com/royalty-free-stock-image-broccoli-steamer-image4403516

  17. Important Vitamin derived Coenzymes • CoA • Includes ADP, niacin, and pantothenic acid • Acetyl transfer NAD • Includes ADP, ribose and niacin. • Reduced to NADH • C=O goal FAD • Includes ADP and riboflavin • Reduced to FADH • C=C goal

  18. Important roles Vitamin derived Coenzymes play • Redox Reactions • Acyl transfer http://www.youtube.com/watch?v=c-f7tc_VO-0

  19. NADH and FADH2 formed NAD+ + 2H -> NADH + H+ ^ reduction of NAD+ X2 (for every pyruvate produced from glycolysis) http://library.thinkquest.org/27819/ch4_6.shtml Count: 2 NADH from glycolysis 1x2 FADH2 from Citric Acid Cycle 1x2 NADH from pyruvate oxidation 3x2 = 6 NADH from Citric Acid Cyle Total: 10 NADH produced in Cellular Respiration

  20. NADH and FADH in ETC • Oxidized give away their electrons. • NAD+ can then be ‘recycled’ • For each NADH, 3 ATP are produced • For each FADH2, 2 ATP are produced http://faculty.ccbcmd.edu/courses/bio141/lecguide/unit1/prostruct/fg5.html NADH -> NAD+ H + 2e- ^oxidation of NADH

  21. Coenzyme A Involved in Acyl Transfer Vital in the beginning of the citric acid cycle What is an acyl group? http://library.thinkquest.org/27819/ch4_6.shtml http://tainano.com/chin/Molecular%20Biology%20Glossary.htm

  22. Works Cited • Dasgupta, S. "Vitamins and Coenzymes." Http://www.youtube.com/watch?v=c-f7tc_VO-0. NPTEL, Mar.-Apr. 2008. Web. Nov. 2011. <http://www.youtube.com/watch?v=c-f7tc_VO-0>. • Anderson, Nester, Pearsall, Roberts. Microbiology, A Human Perspective. McGraw Hill, New York, 2004.139-141. Print. • Smolin, Lori A., and Mary B. Grosvenor. "8." Nutrition: Science and Applications. Hoboken, NJ: Wiley, 2010. 334-410. Print. • Stryer, Lubert. “Coenzymes.” Biochemistry, 4th ed. New York: W. H. Freeman and Company, 1995. Web. Dec. 2011. <http://www.natuurlijkerwijs.com/english/Coenzyms.htm>. • http://www.chemguide.co.uk/organicprops/aminoacids/enzymes.html • http://kentsimmons.uwinnipeg.ca/cm1504/atp.htm • http://www.uic.edu/classes/bios/bios100/lecturesf04am/lect12.htm • http://www.youtube.com/watch?v=juM2ROSLWfw • http://www.youtube.com/watch?v=mfgCcFXUZRk&feature=relmfu

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