Enzyme Peroxidase



Enzymesare biochemical materials made up of complex proteins. These proteinsare usually synthesized by the body cells and they mainly function tospeed up biochemical reactions and processes. Enzymes are thereforebiological catalysts and after their actions on the substrate theyfacilitate the production of the required products. In additionenzymes are usually required in small quantities since they usuallyremain unaltered after catalyzation hence the same enzyme can bereused for another cycle of catalyzation. It is important to notethat enzymes are also very specific. This unique characteristic hasbeen explained by the lock and key hypothesis of enzyme action.Temperature and pH also have an effect on enzyme action and differentenzymes have varied optimum temperature and pH ranges. Lastly, someenzymes require co-enzymes before they are able to catalyze reactionsand their actions can also be hindered by inhibitors (Ophardt,2003).

Enzymeaction is facilitated by the presence of depressions known as activesites which have specific shape and charge. This feature willtherefore allow the binding of a substrate with feature thatcorrespond with the shape and charge of the enzyme to form anenzyme-substrate complex. The required reaction (anabolic orcatabolic) will then take place leading to the formation of therelated products (WorthingtonBiochemical Corporation, 2015).

Theenzyme peroxidase is comprised of a large family of enzymes whosemost favourable substrate is hydrogen peroxide. However, someperoxides are more operative on organic hydrperoxides. Peroxidasesspecifically facilitate the oxidation of compounds with the help ofnaturally occurring peroxides such as hydrogen peroxide. During thisprocess, the hydrogen peroxide is reduced to form water molecules(Maier,2016).In the reaction between hydrogen peroxide and peroxidase, thehydrogen peroxide is the substrate which will bind with the enzymeperoxidase in a reduction-oxidation (redox) reaction which will leadto the formation of two products namely water and oxygen. Thisreaction can be written chemically as follows:

Enzyme Peroxidase

2H2O2(hydrogen Peroxide – Substrate) 2H2O+ O2(Products)

Differentlaboratory tests can be performed to ascertain the different factorsaffecting enzyme catalyzed reactions. These factors that affectenzyme activity include temperature, pH, enzyme concentration andboiling. These tests mainly focus on the varied characteristics ofenzymes and therefore based on these factors the tests willfacilitate the determination of the optimum temperature in whichperoxidase is most active, the optimum pH as well as the effects ofenzyme concentration and boiling in the rate of enzyme activity onthe substrate (Mizobutsi,2010).In addition other tests that can be performed include the testing ofsamples for the presence of peroxidase activity. The samples can beeither plant tissues or animal tissues

itis expected that high enzyme concentration will speed up the rate ofreaction due to the competition of enzyme to the substrate. Lowtemperature is likely to reduce enzyme activity while extremely hightemperature will most likely render the enzyme inactive. This isbecause peroxidase has an optimum temperature of around 350C.Similarly, highly acidic and highly alkaline pH will most likelyreduce the rate of catalysis. An optimum pH can be deduced in thetest. Boiling on the other hand requires temperature of up to 1000Cand most enzymes are usually denatured at very high temperatures(Ophardt,2003).In addition, tissues with the presence of peroxidase activity arelikely to be monitored by measurement of oxygen gas which is producedduring the reaction.


  1. Maier, K. (2016, January 27). What is a Peroxidase? Retrieved March 3, 2016, from Wisegeek: http://www.wisegeek.org/what-is-a-peroxidase.htm

  2. Mizobutsi, G. P. (2010, April). Effect of pH and temperature on peroxidase and polyphenoloxidase activities . Retrieved March 3, 2016, from Scientia Agricola: http://www.scielo.br/scielo.php?script=sci_arttext&amppid=S0103-90162010000200013

  3. Ophardt, C. E. (2003). Role of Enzymes in Biochemical Reactions. Retrieved March 3, 2016, from Virtual Chembook: http://chemistry.elmhurst.edu/vchembook/570enzymes.html

  4. Worthington Biochemical Corporation. (2015). Peroxidase. Retrieved March 3, 2016, from Worthington Biochemical Corporation: http://www.worthington-biochem.com/hpo/default.html