Substrate (biochemistry)

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In biochemistry, a substance is called a substrate that is converted in an enzymatically controlled reaction. In such a reaction, the enzyme cleaves or changes one or more other substances in a catalytic reaction - the substrates.

In chemistry, a substrate is the starting material for catalysis , in the broadest sense a carrier of certain physical, chemical or biological properties that usually change through the reaction (or in the course of a cascade of reactions).

In microbiological experiments, the nutrient medium is also referred to as the substrate.


In Enzymology which is the starting material (starting material) of a by enzyme catalyzed , biochemical reaction as a substrate , respectively.

A simple description of an enzymatic reaction usually looks like this:

The starting material is therefore the substrate of the enzyme in the reaction equation shown and the enzyme-substrate complex is also shown. Sometimes the product does not have a new name, but is also called 'converted substrate' or 'converted substrate'.

Chromogenic and fluorogenic substrates are of particular interest for the detection of enzymes in microorganisms and for determining the activity of enzymes. These substrates are split and a chromogen (dye) or a fluorogen (fluorescent dye) is released. An enzyme activity can be detected by a discoloration or by fluorescence . The enzymatic activity ( enzyme kinetics ) can be determined by means of the intensity of the color or fluorescence .

These substrates are mainly used in ELISA tests and various biochemical tests. In microbiology they are used for chromogenic and fluorogenic media ( nutrient media ) in order to achieve a safer and easier isolation and identification of certain microorganisms.

Individual evidence

  1. Peter Karlson: Short textbook of biochemistry. 9th edition, Georg Thieme, Stuttgart 1974, p. 61.
  2. Entry on substrate. In: Römpp Online . Georg Thieme Verlag, accessed on June 20, 2014.
  3. a b c Michael T. Madigan, John M. Martinko, Jack Parker: Brock Mikrobiologie. German translation edited by Werner Goebel, 1st edition. Spektrum Akademischer Verlag GmbH, Heidelberg / Berlin 2000, ISBN 978-3-8274-0566-1 .
  4. Reinhard Matissek, Frank-M. Schnepel, Gabriele Steiner: Food analysis: basics, methods, applications. 2nd Edition. Springer Verlag, Berlin / Heidelberg / New York 1992, ISBN 3-540-54684-7 .
  5. RD Gonzalez, LM Tamagnini, PD Olmos, GB de Sousa: Evaluation of a chromogenic medium for total coliforms and Escherichia coli determination in ready-to-eat foods. In: Food Microbiology. Volume No. 20, pp. 601-604.
  6. Technical Information Fluorocult® BRILA Broth from Merck KGaA, accessed on February 24, 2013.