Structural Biochemistry/Protein function/Abzyme

What is it?

An abzyme is an antibody that expresses catalytic activity . A single molecule of an antibody-enzyme, or abzyme, is capable of catalyzing the destruction of thousands of target molecules . The efficiency of abzyme technology could permit treatments with smaller doses of medicines at lower costs than are possible today. An abzyme is used to lower the activation energy of a reaction allowing for the transition state to be possible and the product to be formed. Abzymes are typically artificially made by having the immune system make antibodies that bind to a molecule that resembles the transition state (Transition State Analogue) of the catalytic process that the researchers want to emulate. Therefore by creating this antibody, now becoming a catalytic antibody allows for this antibody to act as an abzyme reducing the activation energy of the reaction and allowing for the transition state to occur. Abzymes however do occur naturally in the human body.

Uses in Medicine

Abzyme are currently being researched for the possible use against HIV infection. The abzymes could target a specific site on the HIV infected cells that do not mutate and then make the virus inert. This is an on going research project by the University of Texas Medical School.By exploiting the highly specific antigen binding properties of antibodies, experimental strategies have been made to produce antibodies to catalyze that chemical reactions. These abzymes are chosen from monoclonal antibodies which are created by immunizing mice with haptens which mimic the transition states of enzyme-catalyzed reactions. The rate of this reaction is promoted by enzyme catalysts that stabilize the transition state of this reaction, thereby decreasing the activation energy and allowing for more rapid conversions of substrate product . To successfully create abzymes that are complementary in structure to this transition state, mice were immunized with an aminophosphonic acid hapten . The study of catalytic antibodies as a whole has vastly increased current understanding of the mechanisms of enzyme catalysis and represents another step forward in the attempts to create artificially engineered biological enzymes .

Sources

http://www.uth.tmc.edu/pathology/research/circ/hiv.html - Includes Pictures of Abzymes and how they affect HIV