29+ Important Cofactor Examples That You Should Know

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Some cofactors are synthesised in our body and are mostly organic compounds like ATP, NADP, FADP etc. But some other cofactors are also needed from outside and can be taken into our daily diet. These kinds of cofactors are some vitamins and minerals, and iron-sulphur clusters. Cofactor examples are mentioned below.

  • Copper
  • Magnesium
  • Iron
  • Zinc
  • Calcium
  • Potassium
  • Manganese
  • Nickel
  • Cobalt
  • Selenium
  • Molybdenum
  • Iron-sulphur cluster
  • Chromium
  • Vitamin A
  • Vitamin B2
  • Vitamin C
  • Tungsten
  • Vanadium
  • Cadmium
  • Haem
  • Biotin
  • Coenzyme A
  • Tetrahydrofolate
  • Lipoate
  • Pyridoxal phosphate
  • Thiamine pyrophosphate
  • Niacin
  • Nicotinamide dinucleotide
  • Adenosine triphosphate
  • Flavin adenine dinucleotide

Explain each with source, location and functions

1. Copper

Source: Cytochrome oxidase, Tyrosinase

Location: Mitochondria

Function: This cation is used as an electron transfer intermediate. Many enzymes can function in presence of copper ions like monooxygenases, and tyrosinase to catalyze the hydroxylation of glycosidic bonds and can oxidise the catechols in the melanin biosynthetic pathway.

2. Magnesium

Source: Hexokinase, Pyruvate kinase, Glycosyltransferase, Glucose-6-phosphatase

Location: Cytosol

Function: They are a good the -OH acceptor and have the ability to transfer the P group. They play a major role in chlorophyll as they are the central atom with four porphyrin rings. In our cells, what we know as ATP, the energy currency must bind up with Mg++ ions to become an active ATP i.e., Mg-ATP.   

3. Iron

Source: Nitrogenase, Cytochrome oxidase, Catalase, Peroxidase

Location: Root nodules of legumes, cytoplasm and mitochondria

Function: They play a major role in the photosynthetic organism as they help in electron transfer and catalysis. They are also important to the human body for blood circulation.

4. Zinc

Source: Thiol-ester hydrolases, Aldehyde-lyases, DNA polymerase, Carbonic anhydrase, Carboxy-peptidase

Location: Cytosol of liver and stomach and liver cells, renal tubules

Function: They especially act on C-C bonds. They are the key component of dehydrogenases as they require 4 zinc ions for functioning. They also help in the conversion of superoxide to hydrogen peroxide via superoxide dismutase.

5. Potassium

Source: Pyruvate kinase, Catalase

Location: Cytosol

Function: Very limited number of enzymes required this ion for activation. They are mostly used for carbohydrate metabolism.

6. Manganese

Source: Arginase, Ribonucleotide reductase, D-amino acid ligase

Location: Mitochondria of kidney and prostate and nucleoplasm

Function: They act as a cofactor in almost 6% of the enzymatic reactions in plants. They can catalyse the splitting of H2O and transfer the electrons to drive photosynthesis.

7. Nickel

Source: Urease, Hydrolase, Linear amides

Location: Soil and human body

Function: Besides urease, they also play a crucial role in CO dehydrogenase and acetyl CoA synthase. They maintain the metal homeostasis in methanogens. In contrast, no nickel enzyme has been found in mammalian species. 

8. Cobalt

Source: Nucleotidyl transferase

Location: Cytosol

Function: Besides the component of vitamin B12, it also plays a crucial role in the formation of pre-B and pre-T cells, leading to the production of antioxidant and anti-viral defences in the immune system.

9. Selenium

Source: Glutathione peroxidase

Location: Cytoplasm

Function: They acts as hydrogen donor as it removes hydrogen peroxide from the cells.

10. Molybdenum

Source: Xanthine oxidase, Dinitrogenase, Nitrate reductase

Location: Serum and lungs, procaryotic organism

Function: They also play an essential role in sulfite oxidase. They form the Fe-Mo complex of NR reduce the nitrate into nitrite through NO3 – assimilation pathway

11. Iron-sulphur cluster

Source: Oxidoreductase, Succinate dehydrogenase

Location: Inner-mitochondrial membrane

Function: They play a crucial role in the mitochondrial respiratory chain and protein metabolism.

12. Haem

Source: Phosphoric diester hydrolase

Location: Cytoplasm

Function: Haem is the most important component of our fluid tissues and helps in detoxification from procaryotic to vertebrates.

13. Biotin

Source: Also known as vitamin B7

Location: Eggs, Avocados, salmon, nuts

Function: They are involved in CO2 metabolism. They enhance the catabolic activity of propionyl-CoA-carboxylase. It is a form of vitamin B which boosts the growth of hair follicles.

14. Coenzyme A

Source: Also known as Acetyl coenzyme A, present in meat, vegetables, cereal grains

Location: Mitochondria

Function: They help the transfer of acyl groups. They are used in the oxaloacetic acid cycle which oxidises the pyruvate and is involved in fatty acid metabolism.

15. Tetrahydrofolate

Source: Dihydrofolate reductase

Location: found in both prokaryotes and eucaryotes

Function: They are important to purine synthesis and anabolism of single -C compounds. Folic acids are the prime component of a balanced diet during pregnancy.

16. Lipoate

Source: 2-oxoglutarate dehydrogenase, also known as thioctic acid or lipoic acid

Location: Mitochondria

Function: They act as an electron carrier in the cells and are involved in mitochondrial oxidative phosphorylation.

17. Pyridoxal phosphate

Source: Glycogen phosphorylase, also known as vitamin B6, found in Ginkgo biloba and Arabidopsis thaliana

Location: Muscle and hepatocytes

Function: It is pyridoxal 5- phosphate, stabilises the α carbon of amino acids and performs the metabolism of proteins.

18. Thiamine pyrophosphate

Source: alpha-ketoglutarate dehydrogenase, also known as vitamin B1

Location: Mitochondria

Function: A derivative of thiamine which catalyzes the oxidative decarboxylation and transketolase reactions.

19. Nicotinamide dinucleotide

Source: Also known as NAD(P) (H)

Location: Mitochondrial matrix, Thylakoid of chloroplast

Function: NAD functions in conjugation with enzymes called dehydrogenases, and catalyzes the oxidation-reduction reactions. NADP + is reduced to NADPH in the second electron transport chain of photosynthesis.

20. Adenosine triphosphate (ATP)

Source: ATP synthase

Location: Mitochondria

Function: The chief role of ATP is for the maintenance of respiration itself and to produce heat, light, energy and electricity.

cofactor-examples
Chemical structure of Adenosine triphosphate Image credit; Wikimedia commons

21. Flavin adenine dinucleotide (FDN)

Source: α-glycerophosphate dehydrogenase, Succinate dehydrogenase

Location: Mitochondria

Function: Flavoproteins catalyze the removal of a hydride ion(H–) and hydrogen ion(H+) from a metabolite.

22. Calcium

Source: Hydrolase, Glycosylate, Glycosidase

Location: Endoplasmic reticulum, Lysosome, Golgi apparatus

Function: It is not a cofactor as it does not involve directly in an enzymatic pathway but acts as the precursor for many enzymes like protein phosphatase for allosteric regulation.

23. Riboflavin

Source: Also known as vitamin B2, present in eggs, milk and yoghurt

Location: Erythrocytes and Platelets

Function: It induced the iron acquisition as well as in activation of flavin mononucleotides. It also serves as an electron carrier.

24. Retinal

Source: Retinol dehydrogenase, also known as vitamin A

Location: Rod cells in eyes

Function: They act upon the photoreceptor cells and can convert retinol into retinal via photoisomerization and helps in proper visualizations.

25. Ascorbic acid

Source: Prolyl-3 hydroxylase and lysyl hydroxylase

Location: Rough Endoplasmic Reticulum

Function: It is involved in the synthesis of collagen, catecholamines, histone methylation and other amidated peptide hormones.

26. Niacin

Source: Meat, dairy products, fruits, vegetables and seeweeds, Also known as vitamin B3

Location: All tissues in the body

Function: This behaves as the precursor for nicotinamide adenosine dinucleotide and nicotinamide adenosine dinucleotide phosphate. It also acts as an electron transporter.

27. Tungsten

Source: Aldehyde ferredoxin oxidoreductase

Location: In an archea, Pyrococcus furiosus

Function: It provides the active site in AOR for binding of 2 molybdopterins and is used in the metabolism of aldehydes.

28. Cadmium

Source: Carbonic anhydrase

Location: Brain, Osteoclasts

Function: They are effective in marine phytoplankton like in diatoms. They can induce the production ofc thiols and phytochelatin compounds.

29. Chromium

Source: Chromodulin (an enzyme)

Location: Liver, spleen and bones

Function: It regulates the catabolism of fats and carbs. It also guides the synthesis of cholesterol and fatty acids. Chemically, it is also primarily important for insulin stimulation.

30. Vanadium

Source: Nitrogenase

Location: Root nodules of diazotrophs

Function: It gets associated with iron to form a FeV cluster inside the organism to fix the atmospheric nitrogen into an absorbable form.

Conclusion

As per my knowledge, I would like to conclude that cofactors are non-proteinaceous and are involved in a large number of intracellular reactions. They play a vital role in the regulation of biosynthetic pathways. They are directly or indirectly present in carbohydrate, protein and fatty acid metabolism.

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