Artificial enzyme

For enzyme mimic, see enzyme mimic.
Schematic drawing of artificial phosphorylase

An artificial enzyme is a synthetic, organic molecule prepared to recreate the active site of an enzyme.

Enzyme catalysis of chemical reactions occur with high selectivity and rate in a small part of the enzyme macromolecule known as the active site. There, the binding of a substrate close to functional groups in the enzyme causes catalysis by so-called proximity effects. It is therefore possible to create similar catalysts from small molecule mimics of enzyme active sites by combining, in a small molecule, the ability to bind substrate with catalytic functional groups. Since the artificial enzymes need to bind molecules, they are made based on a host-molecule such as a cyclodextrin, crown ethers or calixarene etc.

A number of artificial enzymes have been reported catalysing various reactions with rate increases up to 103; this is nevertheless substantially lower than natural enzymes that typically causes rate increases above 106. One of the pioneers in artificial enzyme research is chemist Ronald Breslow. He has published a book on the subject entitle Artificial Enzymes.[1]

New approaches based on amino acids or peptides as characteristic molecular moieties have led to a significant expansion of the field of artificial enzymes or enzyme mimics. For instance, recent results by the group of Rob Liskamp[2] have shown that scaffolded histidine residues can be used as mimics of certain metalloproteins and -enzymes. Especially the structural mimicry of certain copper proteins (e.g. hemocyanin, tyrosinase and catechol oxidase), containing so-called type-3 copper binding sites, has been shown. This is a significant improvement since the use of scaffolded histidine residues is one step closer to the mimicry of enzymes by biological relevant species such as amino acids and peptides.[3]

Recently, a new kind of artificial enzymes, nanozymes (or nanozyme), has been reported.[4] Nanozymes are nanomaterials with enzyme-like characteristics.[4] The term of nanozymes was coined by Flavio Manea, Florence Bodar Houillon, Lucia Pasquato, Paolo Scrimin in 2004.[5] (Note: nanozyme (or nanozymes) has also been used in other cases.[6][7][8]) They have been widely used in various areas, such as biosensing, bioimaging, tumor diagnosis and therapy, antibiofouling, etc.[4][9] Several conferences (meetings) has been focused on the nanozymes. In 2015, a workshop for nanozyme has been held in 9th Asian Biophysics Associatation (ABA) Symposium.[10] In Pittcon 2016, a Networking entitled "Nanozymes in Analytical Chemistry and Beyond" is devoted to nanozymes.[11] A book chapter on nanozymes has been written by Xiyun Yan and coworkers.[12]

Timeline of Nanozymes (from Chem Soc Rev)

References

  1. ↑ "Wiley: Artificial Enzymes - Ronald Breslow". as.wiley.com. Retrieved 2015-12-11.
  2. ↑
  3. ↑ Scaffolded amino acids as a close structural mimic of type-3 copper binding sites. H. Bauke Albada, Fouad Soulimani, Bert M. Weckhuysen and Rob M. J. Liskamp, Chem. Commun., 2007, pages 4895-4897, doi:10.1039/B709400K
  4. 1 2 3 Wei, Hui; Wang, Erkang. "Nanomaterials with enzyme-like characteristics (nanozymes): next-generation artificial enzymes". pubs.rsc.org. doi:10.1039/C3CS35486E. Retrieved 2015-12-11.
  5. ↑ "Nanozymes: Gold-Nanoparticle-Based Transphosphorylation Catalysts".
  6. ↑ Hastings, Courtney J.; Fiedler, Dorothea; Bergman, Robert G.; Raymond, Kenneth N. (2008-08-01). "Aza Cope Rearrangement of Propargyl Enammonium Cations Catalyzed By a Self-Assembled "Nanozyme"". Journal of the American Chemical Society 130 (33): 10977–10983. doi:10.1021/ja8013055. ISSN 0002-7863.
  7. ↑ Wang, Zhongliang; Liu, Hongyan; Yang, Soon Hye; Wang, Tie; Liu, Chen; Cao, Y. Charles (2012-07-31). "Nanoparticle-based artificial RNA silencing machinery for antiviral therapy". Proceedings of the National Academy of Sciences 109 (31): 12387–12392. doi:10.1073/pnas.1207766109. ISSN 0027-8424. PMC 3412013. PMID 22802676.
  8. ↑ Jiang, Yuhang; Brynskikh, Anna M.; S-Manickam, Devika; Kabanov, Alexander V. (2015-09-10). "SOD1 nanozyme salvages ischemic brain by locally protecting cerebral vasculature". Journal of Controlled Release 213: 36–44. doi:10.1016/j.jconrel.2015.06.021.
  9. ↑ "Nanozyme brief history".
  10. ↑ "Workshop for nanozymes".
  11. ↑ "Nanozymes at Pittcon 2016".
  12. ↑ 阎锡蕴. 纳米材料新特性及生物医学应用 (第1版 ed.). 北京: 科学出版社. ISBN 9787030418289.
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