No proof for the need of zinc in human cells was shown until the late 1930s where its presence was demonstrated in carbonic anhydrase and the 1960s where it was identified as a necessary element for humans

• Zinc was identified to be essential in fungal growth of yeast as shown by Jules Raulin in 1869 yet no proof for the need of zinc in human cells was shown until the late 1930s where its presence was demonstrated in carbonic anhydrase and the 1960s where it was identified as a necessary element for humans.
  • ^{Maret W (2018). Arruda MA (ed.). “Metallomics: The Science of Biometals and Biometalloids”. Advances in Experimental Medicine and Biology. Cham: Springer International Publishing. 1055: 1–20. doi:10.1007/978-3-319-90143-5_1. ISBN 978-3-319-90143-5. PMID 29884959.} 
• Since then, zinc in human biology has advanced to the point that it is as important as iron. 

• Who is Jules Raulin?
  • In 1883, the École Supérieure de Chimie Industrielle de Lyon (ESCIL) was founded by Jules Raulin, a student of Louis Pasteur. 

• What is carbonic anhydrase?
  • The carbonic anhydrases (or carbonate dehydratases) form a family of enzymes that catalyze the interconversion between carbon dioxide and water and the dissociated ions of carbonic acid (i.e. bicarbonate and hydrogen ions).
    • ^{Badger MR, Price GD (1994). “The role of carbonic anhydrase in photosynthesis”. Annu. Rev. Plant Physiol. Plant Mol. Biol. 45: 369–392. doi:10.1146/annurev.pp.45.060194.002101} 
  • The active site of most carbonic anhydrases contains a zinc ion. They are therefore classified as metalloenzymes. The enzyme maintains acid-base balance and helps transport carbon dioxide.
    •  ^{“PDB101: Molecule of the Month: Carbonic Anhydrase”. RCSB: PDB-101. Retrieved 3 December 2018.}
  • Carbonic anhydrase helps maintain acid–base homeostasis, regulate pH, and fluid balance. Depending on its location, the role of the enzyme changes slightly. For example, carbonic anhydrase produces acid in the stomach lining. In the kidney, the control of bicarbonate ions influences the water content of the cell. The control of bicarbonate ions also influences the water content in the eyes. Inhibitors of carbonic anhydrase are used to treat glaucoma, the excessive build-up of water in the eyes. Blocking this enzyme shifts the fluid balance in the eyes of the patient to reduce fluid build-up thereby relieving pressure.
    •  ^{“PDB101: Molecule of the Month: Carbonic Anhydrase”. RCSB: PDB-101. Retrieved 3 December 2018.}
    • ^{Supuran CT (27 May 2004). “Carbonic Anhydrases: Catalytic and Inhibition Mechanisms, Distribution and Physiological Roles”. In Scozzafava A, Supuran C, Conway J (eds.). Carbonic Anhydrases. Taylor & Francis. doi:10.1201/9780203475300. ISBN 9780203475300.}
  • The Bohr effect is a way to describe hemoglobin’s oxygen binding affinity. The Bohr effect, described by Christian Bohr in 1904, refers to a shift in an oxygen dissociation curve that is caused by a change in concentration of carbon dioxide or a change in the pH. Essentially an increase in carbon dioxide results in lowered blood pH, which lowers oxygen-hemoglobin binding.
    •  ^{“Bohr Effect”. www.pathwaymedicine.org. Retrieved 23 November 2019.} 
  • The opposite is true where a decrease in the concentration of carbon dioxide raises the blood pH which raises the rate of oxygen-hemoglobin binding. Relating the Bohr effect to carbonic anhydrase is simple: carbonic anhydrase speeds up the reaction of carbon dioxide reacting with water to produce hydrogen ions (protons) and bicarbonate ions.
  • To describe equilibrium in the carbonic anhydrase reaction, Le Chatelier’s principle is used. The tissues are more acidic than the lungs because carbon dioxide is produced by cellular respiration and it reacts with water in the tissues to produce the hydrogen protons. Because the carbon dioxide concentration is higher, equilibrium shifts to the right, to the bicarbonate side. The opposite is seen in the lungs, where carbon dioxide is being released so its concentration is lower so equilibrium shifts to the left towards carbon dioxide to try to raise its concentration.
    •  ^{“Le Chatelier’s Principle”. www.chemguide.co.uk. Retrieved 23 November 2019.}
  • Carbonic anhydrase could in principle prove relevant to carbon capture. Some carbonic anhydrases can withstand temperatures up to 107 °C and extreme alkalinity (pH > 10). A pilot run with the more stable CA on a flue stream that consisted of 12–13% mol composition CO₂ had a capture rate of 63.6% over a 60-hour period with no noticeable effects in enzyme performance. CA was placed in a N-methyldiethanolamine (MDEA) solution where it served to increase the concentration difference (driving force) of CO₂ between the flue stream of the power plant and liquid phase in a liquid-gas contactor.
    •  ^{Alvizo O, Nguyen LJ, Savile CK, Bresson JA, Lakhapatri SL, Solis EO, et al. (November 2014). “Directed evolution of an ultrastable carbonic anhydrase for highly efficient carbon capture from flue gas”. Proceedings of the National Academy of Sciences of the United States of America. 111 (46): 16436–41. Bibcode:2014PNAS..11116436A. doi:10.1073/pnas.1411461111. PMC 4246266. PMID 25368146}
  • Lots more here
  • Carbonic anhydrase inhibitors are a class of pharmaceuticals that suppress the activity of carbonic anhydrase. Their clinical use has been established as anti-glaucoma agents, diuretics, antiepileptics, in the management of mountain sickness, gastric and duodenal ulcers, idiopathic intracranial hypertension, neurological disorders, or osteoporosis.
    • ^{Supuran CT, Scozzafava A, Conway J, eds. (2004). Carbonic anhydrase: its inhibitors and activators. Boca Raton: CRC Press. ISBN 978-0-415-30673-7.}
    • ^{Supuran, Claudiu T; Scozzafava, Andrea (2000). “Carbonic anhydrase inhibitors and their therapeutic potential”. Expert Opinion on Therapeutic Patents. 10 (5): 575–600. doi:10.1517/13543776.10.5.575}
    • ^{Supuran, Claudiu T.; Scozzafava, Andrea; Casini, Angela (2003). “Carbonic anhydrase inhibitors”. Medicinal Research Reviews. 23 (2): 146–89. doi:10.1002/med.10025. PMID 12500287}
    • More here