Biology:Silicases
From HandWiki
The silicases are a family of enzymes that catalyze rearrangement of silicon-oxygen bonds and are found in some sea sponges.[1] [2]
The by-product of this reaction is silicic acid. [3]
A zinc atom is held in place by three histidine residues. A fourth position on the zinc extracts a hydroxy group from water.
This reacts with an amorphous fragment of hydrated silica to break off silicic acid and leave zinc attached to the larger silica frament.
- Zn-O-H + Si-O-Si(OH)3 → Zn-O-Si + H-O-Si(OH)3
This is then hydrolysed: [1]
- Zn-O-Si + H2O → Zn-OH + HO-Si
Silicases are related to a more common enzyme in animals, carbonic anhydrase. In the human body the carbonic anhydrase most similar to the sponge silicase is type II (CA-II).[1]
[4]
References
- ↑ 1.0 1.1 1.2 Schröder, Heinz C.; Krasko, Anatoli; Le Pennec, Gaël; Adell, Teresa; Wiens, Matthias; Hassanein, Hamdy; Müller, Isabel M.; Müller, Werner E. G. (2003). "Silicase, an Enzyme Which Degrades Biogenous Amorphous Silica: Contribution to the Metabolism of Silica Deposition in the Demosponge Suberites domuncula". in Müller, Werner E. G.. Silicon Biomineralization: Biology — Biochemistry — Molecular Biology — Biotechnology. Progress in Molecular and Subcellular Biology. 33. Springer-Verlag Berlin Heidelberg. pp. 249–268. doi:10.1007/978-3-642-55486-5_10. https://link.springer.com/chapter/10.1007/978-3-642-55486-5_10. Retrieved 12 January 2026.
- ↑ Enhrlich, Hermann; Demadis, Konstantinos D.; Pokrovsky, Oleg; Koutsoukos, Petros G. (2010). "Modern Views on Desilicification: Biosilica and Abiotic Silica Dissolution in Natural and Artificial Environments". Chemical Reviews 110 (8). doi:10.1021/cr900334y. https://pubs.acs.org/doi/10.1021/cr900334y.
- ↑ Kaur, Prabhjot; Sharma, Anjali; Bhardwaj, Nishi Kant; Singh, Amarjit; Dalal, Sunita; Sharma, Jitender (2022). "A novel, simple, and quick plate assay to screen silicolytic bacteria and silicase production using different substrates". Bioresource Technology Reports (Elsevier) 17. https://www.sciencedirect.com/science/article/abs/pii/S2589014X22000287. Retrieved 12 January 2026.
- ↑ Angeli, Andrea; De Luca, Viviana; Capasso, Clemente; Di Constanzo, Luigi F; Supuran, Claudiu T (2024). "Comparative CO2 and SiO2 hydratase activity of an enzyme from the siliceous demosponge Suberitesdomuncula". Arch Biochem Biophys 758. doi:10.1016/j.abb.2024.110074. https://linkinghub.elsevier.com/retrieve/pii/S0003986124001954. Retrieved 12 January 2026.
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