Enzymes

Edited by Jamie (ScienceAid Editor), Taylor (ScienceAid Editor)

Ad

How Enzymes Work

Enzymes are proteins that act as biological catalysts, which means their function in the body is to vastly increase the rate of reaction between chemicals that would not otherwise happen: thus making life possible. Enzymes work by reducing the activation energy of a reaction, this means that with an enzyme present, less energy is needed for the reaction to happen and hence it allows that reaction to occur. For an enzyme reaction to happen, the substrate (chemicals that are being reacted together) goes to the active site (the part of the enzyme that does the work). Crucially, it is the enzyme's shape that is important.

Was this helpful? Yes | No | I need help

The induced fit hypothesis explains how the enzymes work. The active site of an enzyme is the area where reactions take place. The substrate is the chemical that the enzyme is reacting together. According to this explanation for how enzymes work, the two do not fit perfectly, and so the shape of the active site changes slightly to fit. The reaction takes place and the enzyme returns to its original shape.

Was this helpful? Yes | No | I need help

induced fit hypothesis diagram

Factors Affecting Enzyme Activity

  1. 1
    Temperature
    .
    Temperature has an important influence on the rate of activity of an enzyme. To begin with, if you increase temperature, the rate of reaction goes up because the enzyme and substrates are moving about more, and have more energy. However, if you go beyond an optimum point, the activity decreases. This is because the enzyme denatures as hydrogen bonds break, and the enzyme looses its distinctive shape. A similar effect is seen when pH is changed.
    Advertisement
    Was this step helpful? Yes | No | I need help
  2. 2
    Substrate Concentration
    .
    Increasing substrate concentration will increase the reaction rate, but eventually, this rate will level out because the enzymes can only do so much work and the maximum number are being used up.
    Was this step helpful? Yes | No | I need help
  3. 3
    Inhibitors
    .
    Enzyme activity can be reduced by the presence of inhibitors; there are two types.  
    1. A competitive inhibitor has a similar structure to the substrate - so it can fit into the active site and it stops the enzyme catalyzing the actual substrate. All the time, the rate of reaction is reduced.
    2. A non-competitive inhibitor binds to part of the enzyme. This alters its shape and therefore stops it from working correctly. Many poisons are this type of inhibitor, for example: cyanide.
    Was this step helpful? Yes | No | I need help
  4. 4
    Allosteric Site
    .
    Another way of affecting the rate is molecules binding to the allosteric site on an enzyme. This is another part (not the active site) that tells the enzyme to work or not. The presence of these molecules will inhibit or activate the enzyme. However only a few very special enzymes do this.
    Was this step helpful? Yes | No | I need help
    Advertisement

Digestive Enzymes

Because of their importance, we will look at the different digestive enzymes in the table below.

Substance Enzymes What Happens Carbohydrates
Amylase Disaccharidases The salivary amylase begins digestion in the mouth, but not much happens since food only stays there for a short while, but it keeps the mouth clean Amylase from the pancreas breaks down starch into maltose. When the maltose gets into the [[biology/humans/digestion.htm]l ileum], the last stage of digestion takes place and the disaccharides are broken into glucose so they can be absorbed by the process of [biology/cell/transport.html active transport]].
Proteins Endopeptidases These are produced in the pancreas and also as pepsin in gastric juice. This enzyme slices up polypeptides into smaller ones of about 6-12 monomers. It does this at different points depending on the enzyme. This also leaves a lot of ends to help the next enzyme.
Proteins Exopeptidases These proteins live in the ileum membrane, they finish off the job and break the proteins into individual amino acids; which can now be absorbed into the blood stream. Triglycerides Lipase

Referencing this Article

If you need to reference this article in your work, you can copy-paste the following depending on your required format:

APA (American Psychological Association)
Enzymes. (2017). In ScienceAid. Retrieved Apr 29, 2017, from https://scienceaid.net/biology/biochemistry/enzymes.html

MLA (Modern Language Association) "Enzymes." ScienceAid, scienceaid.net/biology/biochemistry/enzymes.html Accessed 29 Apr 2017.

Chicago / Turabian ScienceAid.net. "Enzymes." Accessed Apr 29, 2017. https://scienceaid.net/biology/biochemistry/enzymes.html.

If you have problems with any of the steps in this article, please ask a question for more help, or post in the comments section below.

Comments

ScienceAid welcomes all comments. If you do not want to be anonymous, register or log in. It is free.

Ask the author

Jamie
Featured Author
166 Articles Started
1,284 Article Edits
43,715 Points
Jamie is a featured author with ScienceAid. Jamie has achieved the level of "Captain" with 43,715 points. Jamie has started 166 articles (including this one) and has also made 1,284 article edits. 105,000 people have read Jamie's article contributions.
Jamie's Message Board
Jamie: Hi, my name is Jamie.
Jamie: Can I help you with your problem about "Enzymes"?
 

Article Info

Categories : Biochemistry

Recent edits by: Jamie (ScienceAid Editor)

Share this Article:

Thanks to all authors for creating a page that has been read 20 times.

Do you have a question not answered in this article?
Click here to ask one of the writers of this article
x

Thank Our Volunteer Authors.

Would you like to give back to the community by fixing a spelling mistake? Yes | No