Protease The Protein Enzyme

What is an Enzyme?

Enzymes are macromolecular biological catalysts. They are produced by living organisms to catalyze various biochemical reactions. Enzymes can be found throughout the whole body, each having their own specific role.

Creation of an enzyme

An enzyme is made of anywhere between 100 and 1,000 amino acids strung together in a very specific and unique order. Enzymes are a type of protein, and like other proteins, they are made by the translation of the genetic code into a particular sequence of amino acids by ribosomes. After the enzyme is created as a chain of amino acids, it folds into a particular shape and often binds to other compounds, known as cofactors, before it becomes fully functional.


A photo of HIV-1 Protease


Proteases are enzymes that catalyze the breakdown of proteins. Proteases perform proteolysis, or protein catabolism of hydrolysis of peptide bonds. Protein breakdown is a normal process necessary to maintain cellular homeostasis. Active proteases can be found throughout your body, including the digestive tract, inside cells and circulating in the blood.



Proteases are often activated by either thrombin or zymogen. Zymogens, or proenzymes, are inactive substances that are converted into an enzyme when activated by another enzyme. Zymogen/Protease reactions mostly happen within the digestive system. Thrombin is a form of protease that is found in the circulatory system. It is an enzyme in blood plasma that assists in the creation of fibrin and clotting. Thrombin/Protease reactions occur within the blood stream during clotting processes.

Additional Uses of Protease

  • Proteases are often used by biscuit manufacturers to lower the protein level of flour.
  • Along with amylase and glucanases, protease can be used to split polysaccharides and proteins in malts.
  • Proteases can be used to remove cloudiness produced during the storage of beer.
  • Proteases are also used in detergents and soaps to help remove protein stains from clothing
  • Proteases are also sold as dietary supplements.

Controlling Enzymes

The cell uses specific molecules to regulate enzymes in order to promote or inhibit certain chemical reactions. Sometimes it is necessary to inhibit an enzyme to reduce a reaction rate, and there is more than one way for this inhibition to occur. An inhibitor molecule whose structure is similar to a certain enzyme's substrate may bind with an enzyme at the activation site to stop any reaction from occurring. An inhibitor molecule may also bind to an enzyme at a location that is not the activation site, or an allosteric site. A substrate may still bind with that enzyme, but the inhibitor molecule changes the shape of the enzyme making it unable to catalyze that reaction.

Additional Information

Works Cited

  • Boundless. "Control of Metabolism Through Enzyme Regulation - Boundless Open Textbook." Boundless. Boundless, 26 May 2016. Web. 13 Apr. 2017.
  • Crosier, Michael. "Function of Proteases." LIVESTRONG.COM. Leaf Group, 03 Nov. 2013. Web. 13 Apr. 2017.
  • Boundless. "Enzymes Used in Industry - Boundless Open Textbook." Boundless. Boundless, 08 Nov. 2016. Web. 13 Apr. 2017.
  • Berg, Jeremy M. "Many Enzymes Are Activated by Specific Proteolytic Cleavage." Biochemistry. 5th edition. U.S. National Library of Medicine, 01 Jan. 1970. Web. 13 Apr. 2017.

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