5 by: Jessica Whitehouse
Student – Jessica Whitehouse
Enzyme: Adenosine deaminase, EC 3.5.4.4
What does the enzyme do? Adenosine deaminase (ADA) is responsible for breaking down adenosine to inosine and deoxyadenosine to deoxyinosine. You’ll see in my animation that I focused on the breakdown of deoxyadenosine as it is found to be more harmful to human white blood cells in large quantities. The zinc cation adjacent to the water uses its electrophilic properties to help activate the chemical process. The nitrogen by His238 attacks the hydrogen in the water, which is already hydrogen bonded to that nitrogen so that the electrons from the H can be transferred to the adjacent oxygen. The attacking oxygen can now attack a carbon atom on the deoxyadenosine. Electrons on the deoxyadenosine are then shifted and used to attack ADA on an H-O near Gly217. The newly negatively charged oxygen then attacks the H-O adjacent to the zinc cation, which shifts the electrons to form the characteristic double-bonded oxygen on deoxyinosine and eliminates the NH2.
Where is the enzyme found? ADA is found within all cells, but the highest concentration is found in immune system cells. Specifically, ADA is the most common in lymphocytes, also known as white blood cells. Lymphocytes are made within the bone marrow and then distributed to the blood and lymph tissue.
Fun Facts!
★ The gene for ADA production is found in Chromosome 20.
★ Deoxyadenosine is produced from the adenosine nucleotide when DNA is broken down.
References:
Cristalli, G., Costanzi, S., Lambertucci, C., Lupidi, G., Vittori, S., Volpini, R., & Camaioni, E. (2001). Adenosine deaminase: Functional implications and different classes of inhibitors.
Medicinal Research Reviews, 21(2), 105–128. https://doi.org/10.1002/1098-1128(200103)21:2<105::aid-med1002>3.0.co;2-u
Gene: ADA. Summary – homo_sapiens – GRCH37 archive browser 112. (n.d.). https://grch37.ensembl.org/Homo_sapiens/Gene/Summary?db=core%3Bg
U.S. National Library of Medicine. (2024, May 21). Adenosine deaminase deficiency: MedlinePlus Genetics. MedlinePlus.
https://medlineplus.gov/genetics/condition/adenosine-deaminase-deficiency/#:~:text=The%20adenosine%20deaminase%20enzyme%20works,deoxyinosine%2C%20which%20i
s%20not%20harmful
U.S. National Library of Medicine. (2024a, May 21). Ada Gene: MedlinePlus genetics. MedlinePlus. https://medlineplus.gov/genetics/gene/ada/#:~:text=The%20function%20of%20the%20adenosine,deoxyinosine%2C%20which%20is%20not%20harmful
Image references:
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68605666. Dreamstime. https://www.dreamstime.com/stock-illustration-cute-girl-queen-female-character-princess-costume-crown-scepter-white-background-image68605666
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