The key difference between specificity and selectivity is that specificity is the ability to assess the exact component in a mixture, whereas selectivity is the ability to differentiate the components in a mixture from each other.
Specificity and selectivity are important in analyzing a sample containing a mixture of different compounds. The terms specificity and selectivity are discussed mainly under enzyme-substrate interactions. We can describe specificity regarding substrates and selectivity regarding enzymes.
CONTENTS
1. Overview and Key Difference
2. What is Specificity
3. What is Selectivity
4. Side by Side Comparison – Specificity vs Selectivity in Tabular Form
5. Summary
What is Specificity?
Specificity is the ability to assess the exact components in a mixture. Moreover, specificity measures the degree of interference by other substances present in a sample during the analysis of a particular analyte. Therefore, in enzyme-substrate interactions, this term describes the binding of an enzyme with a “specific” substrate. That means; it is the ability of an enzyme to catalyze a particular biochemical reaction without being involved in the side reactions that takes place at the same place. Moreover, when determining the specificity, it is not important to identify the other substrate; it is only required to identify only the desired analyte in the mixture.
What is Selectivity?
Selectivity is the ability to differentiate the components in a mixture from each other. Usually, selectivity describes the same idea as specificity but their definitions are a little bit different from each other in that, specificity describes finding the exact analyte while selectivity describes the differentiation of components in a mixture. In other words, specificity does not require the identification of all the components in the mixture, but selectivity does need that. We need to consider selectivity when we are going to analyze several different analytes in a mixture rather than a single analyte.
Figure 01: Selectivity of Components that Passes through a Cell Membrane
For example, when determining the selectivity of an enzyme, we can consider all the components in a mixture the enzyme is going to bind with. It is because some enzymes can act on a class of compounds (that are structurally related to each other) rather than a single compound. Moreover, in chromatographic techniques, we finally get a chromatogram with several peaks which describes the several selected analytes in the sample we analyzed.
What is the Difference Between Specificity and Selectivity?
The terms specificity and selectivity are discussed under enzyme-substrate interactions. The key difference between specificity and selectivity is that specificity is the ability to assess the exact component in a mixture whereas selectivity is the ability to differentiate the components in a mixture from each other. Furthermore, if we consider the theory behind these concepts, the specificity describes finding the exact analyte in a mixture while the selectivity describes finding several analytes in a mixture. So, this is also a significant difference between specificity and selectivity.
In determining specificity, we need to identify only the required analyte; however, in determining selectivity, we can identify several important components in a mixture. For instance, substrate specificity determines the specific substrate that is going to bind with a particular enzyme while enzyme selectivity determines the substrates with which the enzyme is going to bind with. Other examples for specificity includes HPLC techniques; chromatographic techniques are examples for selectivity.
Summary – Specificity vs Selectivity
The terms specificity and selectivity are discussed under enzyme-substrate interactions. The key difference between specificity and selectivity is that specificity is the ability to assess the exact component in a mixture, whereas selectivity is the ability to differentiate the components in a mixture from each other.
Reference:
1. Roy, Anindya Ghosh. What Is the Difference between Specificity and Selectivity?, Available here.
2. “Enzyme Specificity vs Selectivity.” Chemistry Stack Exchange, 1 July 1966, Available here.
3. “Binding Selectivity.” Wikipedia, Wikimedia Foundation, 13 June 2019, Available here.
Image Courtesy:
1. “Mechanism of a Potassium Channel” By Mababat – Own work (CC BY-SA 3.0) via Commons Wikimedia