Abzyme

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An abzyme

systemic lupus erythematosus, where they can bind to and hydrolyze DNA.[1] To date abzymes display only weak, modest catalytic activity and have not proved to be of any practical use.[4] They are, however, subjects of considerable academic interest. Studying them has yielded important insights into reaction mechanisms, enzyme structure and function, catalysis, and the immune system itself.[4]

Enzymes function by lowering the activation energy of the transition state of a chemical reaction, thereby enabling the formation of an otherwise less-favorable molecular intermediate between the reactant(s) and the product(s). If an antibody is developed to bind to a molecule that is structurally and electronically similar to the transition state of a given chemical reaction, the developed antibody will bind to, and stabilize, the transition state, just like a natural enzyme, lowering the activation energy of the reaction, and thus catalyzing the reaction. By raising an antibody to bind to a stable transition-state analog, a new and unique type of enzyme is produced.

So far, all catalytic antibodies produced have displayed only modest, weak catalytic activity. The reasons for low catalytic activity for these molecules have been widely discussed. Possibilities indicate that factors beyond the binding site may play an important role, in particular through protein dynamics.[5] Some abzymes have been engineered to use metal ions and other cofactors to improve their catalytic activity.[6][7]

History

The possibility of catalyzing a reaction by means of an antibody which binds the transition state was first suggested by

Richard A. Lerner received the prestigious Wolf Prize in Chemistry for developing catalytic antibodies for many reactions and popularizing their study into a significant sub-field of enzymology.[9]

Abzymes in healthy human breast milk

There are a broad range of abzymes in healthy human breast milk with DNAse, RNAse, and protease activity.[4]

Potential HIV treatment

In a June 2008 issue of the journal Autoimmunity Review,

T lymphocytes
, the key cell in cell-mediated immunity. Once infected by HIV, patients produce antibodies to the more changeable parts of the viral coat. The antibodies are ineffective because of the virus' ability to change their coats rapidly. Because this protein gp120 is necessary for HIV to attach, it does not change across different strains and is a point of vulnerability across the entire range of the HIV variant population.

The abzyme does more than bind to the site: it catalytically destroys the site, rendering the virus inert, and then can attack other HIV viruses. A single abzyme molecule can destroy thousands of HIV viruses.

References

  1. ^ a b "Abzymes: Absource". crdd.osdd.net. Retrieved 2022-06-02.
  2. ^ "Study Notes on Abzymes (With Diagram)". Biology Discussion. 2016-02-24. Retrieved 2022-06-02.
  3. S2CID 39930319
    .
  4. ^ a b c Barrera, G. J., Portillo, R., Mijares, A., Rocafull, M. A., del Castillo, J. R., & Thomas, L. E. (2009). Immunoglobulin A with protease activity secreted in human milk activates PAR-2 receptors, of intestinal epithelial cells HT-29, and promotes beta-defensin-2 expression. Immunology letters, 123(1), 52-59.
  5. PMID 16248667
    .
  6. ^ Nicholas, Ken (January 30, 2004). "Catalytic Metalloantibodies: Biology in Service of Chemistry" (PDF). southeastern.edu. Archived (PDF) from the original on 2022-10-09. Retrieved 2019-11-11.
  7. ^ "Metalloantibodies. - Science - HighBeam Research". 23 March 2015. Archived from the original on 23 March 2015.
  8. ^ "Antibody Catalysis, Linus Pauling, W.P. Jencks, Kohler and Milstein". www.dsch.univ.trieste.it.
  9. ^ "Organic Chemist Peter Schultz wins Wolf Prize in Chemistry". www2.lbl.gov.
  10. PMID 18558365
    .
  11. ^ "UT pathologists believe they have pinpointed Achilles heel of HIV". physorg.com. Retrieved 2008-07-16.
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