A prosthetic group is a non-protein (non-amino acid) component of a conjugated protein that is important in the protein's biological activity.[1] The prosthetic group may be organic (such as a vitamin, sugar, or lipid) or inorganic (such as a metal ion). Prosthetic groups are bound tightly to proteins and may even be attached through a covalent bond. They often play an important role in the function of enzymes. A protein without its prosthetic group is called an apoprotein, while a protein combined with its prosthetic group is called a holoprotein.
Prosthetic groups are a subset of cofactors and differ from coenzymes in that they bind permanently to the enzyme as opposed to temporarily for coenzymes.[2] In enzymes, prosthetic groups are involved in the active site in some way.
The heme group in hemoglobin is a prosthetic group. Further examples of organic prosthetic groups are vitamin derivatives: thiamine (vitamin B1), thiamine pyrophosphate, pyridoxal-phosphate and biotin. Since prosthetic groups are often vitamins or made from vitamins, this is one of the reasons why vitamins are required in the human diet. Inorganic prosthetic groups are usually transition metal ions such as iron (in heme groups, for example in cytochrome c oxidase and hemoglobin), zinc (for example in carbonic anhydrase), magnesium (for example in some kinases), and molybdenum (for example in nitrate reductase).
List of prosthetic groups
| Prosthetic group | Function | Distribution |
| Flavin mononucleotide [3] | Redox reactions | Bacteria, archaea and eukaryotes |
| Flavin adenine dinucleotide [3] | Redox reactions | Bacteria, archaea and eukaryotes |
| Pyrroloquinoline quinone [4] | Redox reactions | Bacteria |
| Pyridoxal phosphate [5] | Transamination, decarboxylation and deamination | Bacteria, archaea and eukaryotes |
| Biotin [6] | Carboxylation | Bacteria, archaea and eukaryotes |
| Methylcobalamin [7] | Methylation and isomerisation | Bacteria, archaea and eukaryotes |
| Thiamine pyrophosphate [8] | Decarboxylation | Bacteria, archaea and eukaryotes |
| Heme [9] | Oxygen binding and redox reactions | Bacteria, archaea and eukaryotes |
| Molybdopterin [10][11] | Oxygenation reactions | Bacteria, archaea and eukaryotes |
| Lipoic acid [12] | Redox reactions | Bacteria, archaea and eukaryotes |
References
- ^ de Bolster, M.W.G. (1997). "Glossary of Terms Used in Bioinorganic Chemistry: Prosthetic groups". International Union of Pure and Applied Chemistry. Retrieved 2007-10-30.
- ^ de Bolster, M.W.G. (1997). "Glossary of Terms Used in Bioinorganic Chemistry: Cofactors". International Union of Pure and Applied Chemistry. Retrieved 2007-10-30.
- ^ a b Joosten V, van Berkel WJ (2007). "Flavoenzymes". Curr Opin Chem Biol. 11 (2): 195–202. doi:10.1016/j.cbpa.2007.01.010. PMID 17275397.
- ^ Salisbury SA, Forrest HS, Cruse WB, Kennard O (1979). "A novel coenzyme from bacterial primary alcohol dehydrogenases". Nature. 280 (5725): 843–4. doi:10.1038/280843a0.
{{cite journal}}: CS1 maint: multiple names: authors list (link) PMID 471057 - ^ Eliot AC, Kirsch JF (2004). "Pyridoxal phosphate enzymes: mechanistic, structural, and evolutionary considerations". Annu. Rev. Biochem. 73: 383–415. doi:10.1146/annurev.biochem.73.011303.074021. PMID 15189147.
- ^ Jitrapakdee S, Wallace JC (2003). "The biotin enzyme family: conserved structural motifs and domain rearrangements". Curr. Protein Pept. Sci. 4 (3): 217–29. doi:10.2174/1389203033487199. PMID 12769720.
- ^ Banerjee R, Ragsdale SW (2003). "The many faces of vitamin B12: catalysis by cobalamin-dependent enzymes". Annu. Rev. Biochem. 72: 209–47. doi:10.1146/annurev.biochem.72.121801.161828. PMID 14527323.
- ^ Frank RA, Leeper FJ, Luisi BF (2007). "Structure, mechanism and catalytic duality of thiamine-dependent enzymes". Cell. Mol. Life Sci. 64 (7–8): 892–905. doi:10.1007/s00018-007-6423-5. PMID 17429582.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Wijayanti N, Katz N, Immenschuh S (2004). "Biology of heme in health and disease". Curr. Med. Chem. 11 (8): 981–6. doi:10.2174/0929867043455521. PMID 15078160.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Mendel RR, Hänsch R (2002). "Molybdoenzymes and molybdenum cofactor in plants". J. Exp. Bot. 53 (375): 1689–98. doi:10.1093/jxb/erf038. PMID 12147719.
- ^ Mendel RR, Bittner F (2006). "Cell biology of molybdenum". Biochim. Biophys. Acta. 1763 (7): 621–35. doi:10.1016/j.bbamcr.2006.03.013. PMID 16784786.
- ^ Bustamante J, Lodge JK, Marcocci L, Tritschler HJ, Packer L, Rihn BH (1998). "Alpha-lipoic acid in liver metabolism and disease". Free Radic. Biol. Med. 24 (6): 1023–39. doi:10.1016/S0891-5849(97)00371-7. PMID 9607614.
{{cite journal}}: CS1 maint: multiple names: authors list (link)
See also
External links
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