A biocatalyst is a particle that acts as a catalyst and accelerates at least one reaction. Although the biocatalyst is chemically involved during the reaction and is changed as a result, it returns to its initial state after the reaction has ended, so that it can catalyze many reaction cycles in succession .
Jons Jakob Berzelius first used knowingly a biocatalyst for the hydrolysis of starch .
Enzymes, ribozymes and cells
Most biocatalysts are enzymes , more rarely ribozymes or whole cells . As proteins, enzymes consist of a chain of amino acids . A substrate is the compound that is converted by an enzyme. An inhibitor is a compound that slows down or prevents an enzymatic reaction .
Enzymes are often optimized in the course of protein engineering and also bound to a carrier material; such a biocatalyst is then called an immobilized recombinant enzyme. The advantages of this technology are that the biocatalyst then remains stable for longer and can be removed more easily from the reaction mixture.
If the biocatalyst consists of ribonucleotides , then it is a catalytically active ribonucleic acid , which is functionally one of the rarer ribozymes .
Biocatalysts enable the biochemical reactions and physiological processes of all living things . Life as we find it on earth would be unthinkable without biocatalysts .
Biocatalysts are also used in organic synthesis because they can be used to produce products with high selectivity under comparatively mild reaction conditions . Another advantage of biocatalysts is that no racemates are obtained (the formation of an enantiomer is usually highly preferred). Such high enantiomeric excesses are generally not achieved in a chemical enantioselective synthesis .
Biocatalysts used for industrial purposes are z. B. lipases , esterases , proteases , amylases and oxidases . The biocatalysts are not only used in aqueous reaction media ( buffers ), but are also active in organic solvents. It has also been known since the mid-80s that biocatalysts can be used in supercritical fluids.
An example of a biocatalyst is chymotrypsin , it catalyzes the cleavage of protein chains. In the laboratory, this would require concentrated hydrochloric acid at boiling point.
- ↑ AS Bommarius, JK Blum, MJ Abrahamson: Status of protein engineering for biocatalysts: how to design an industrially useful biocatalyst. In: Current opinion in chemical biology. Volume 15, Number 2, April 2011, pp. 194-200, doi: 10.1016 / j.cbpa.2010.11.011 . PMID 21115265 .
- ^ LR Jarboe, LA Royce, P. Liu: Understanding biocatalyst inhibition by carboxylic acids. In: Frontiers in microbiology. Volume 4, 2013, p. 272, doi: 10.3389 / fmicb.2013.00272 . PMID 24027566 . PMC 3760142 (free full text).
- ↑ L. Fernández-Arrojo, ME Guazzaroni, N. López-Cortés, A. Beloqui, M. Ferrer: Metagenomic era for biocatalyst identification. In: Current Opinion in Biotechnology. Volume 21, number 6, December 2010, pp. 725-733, doi: 10.1016 / j.copbio.2010.09.006 . PMID 20934867 .
- ↑ M. Wang, T. Si, H. Zhao: Biocatalyst development by directed evolution. In: Bioresource Technology . Volume 115, July 2012, pp. 117–125, doi: 10.1016 / j.biortech.2012.01.054 . PMID 22310212 . PMC 3351540 (free full text).
- ↑ James Darnell, Harvey F. Lodish, Lothar Träger: Molecular Cell Biology . 2nd Edition. De Gruyter, Berlin [a. a.] 1996, ISBN 3-11-014460-3 .