36 by: Allie Shiyuk
Student – Allie Shiyuk
Name of enzyme and E.C. number: Glycerol dehydrogenase, E.C. 1.1.1.6
Where is the enzyme found? Glycerol dehydrogenase (GlyDH) has been found in a variety of organisms, ranging from bacteria to mammals. However, the enzyme found in mammals, such as in rat livers and rabbit skeletal muscles, is involved in biochemical processes and systems that differ significantly from those found in bacteria. GlyDH has been isolated from several bacteria; most studies of this enzyme have been performed on GlyDH from Bacillus stearothermophilus because of its stability at high temperatures.
What does the enzyme do? Glycerol dehydrogenase plays a pivotal role in anaerobic glycerol metabolism in microorganisms. Under anaerobic conditions, GlyDH catalyses the oxidation of glycerol to dihydroxyacetone, with the simultaneous reduction of NAD+ to NADH and H+. Following, dihydroxyacetone can be phosphorylated by dihydroxyacetone kinase to form dihydroxyacetone phosphate, which can enter the glycolytic pathway for further oxidation. Ultimately, the function of glycerol dehydrogenase allows for anaerobic microorganisms to use glycerol as a source of carbon to produce ATP energy.
Interesting facts and important information on this enzyme – Although glycerol dehydrogenase is thought to belong to the iron-containing alcohol dehydrogenase family, it is dependent on the presence of Zn 2+ to function. Zinc is a cofactor that functions in stabilizing the negative charge on the oxygen atom in the alkoxide intermediate formed through the oxidative reaction of glycerol to dihydroxyacetone. The gene that encodes production of this protein is gldA. The product of glycerol dehydrogenase, dihydroxyacetone, has various commercial purposes. DHA, when combined with pyruvate, can be sold as a nutritional supplement, functioning to increase lean muscle mass in athletes. In addition, DHA has been included in sunless tanning products since the 1960s and is still the main active ingredient in tanning products today.
References
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Biology Online. (2022). Glycerol. https://www.biologyonline.com/dictionary/glycerol
European Bioinformatics Institute. (2018). Chebi: 16016- dihydroxyacetone. https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI%3A16016#:~:text=Dihydroxyacetone%20(%20%3B%20DHA)%2C%20also,by%20the%20fermentation%20of%20glycerin
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Robinson, P. K. (2015). Enzymes: Principles and biotechnological applications. National Library of Medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4692135/
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Trypanocyc. (2024). MetaCyc enzyme: glycerol dehydrogenase. http://vm-trypanocyc.toulouse.inra.fr/META/NEW-IMAGE?type=ENZYME-IN-PATHWAY&object=CPLX-3681
UniProt. (2024). P0A9S5 GLDA_ECOLI. https://www.uniprot.org/uniprotkb/P0A9S5/entry
Van Noorden, C. J. F. (2014). Oxidoreductase. ScienceDirect. https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/oxidoreductase
