Question

Describe how changing one amino acid in an enzyme could affect the function of that enzyme. Be sure to include in your answer how this change could affect the various levels of protein structure and function. Be specific with a concrete example of the change e.g. hydrophobic amino acid for a hydrophilic amino acid, or an ionic amino acid for a neutral amino acid. (Terms you want to include in your answer- active site, lock and key model or induced fit model- i.e. how does change in 3-d structure effect function of the enzyme).

Answer 1

Most Enzymes are proteins. Their catalytic activity depends upon on the integrity of their native protein conformation. if an enzyme is denatured or dissociated into its subunits, catalytic activity is usually lost.Enzymes are particular in action which potential one enzyme is able to accomplish only one reaction.Enzymes are denatured by severe temperatures (above 40 ranges celsius), and as quickly as an enzyme has been denatured you would be unable to lead them to artwork back. The optimal temperature for enzymes to artwork is 38 ranges celsius. Denaturation is a process in which proteins lose their native conformation. Denaturation includes the breaking of non-covalent (ionic interaction, H-bond, van der Waals force of interaction, hydrophobic interaction) and covalent ( disulfide bonds) bonds. Denaturation usually does not include the breaking of peptide bonds.depending on the degree of denaturation, the molecule may partially or completely lose its biological activity. Since the native conformation is usually the most water-soluble, disrupting the secondary and tertiary structure cause change in solubility and frequently results in precipitation of the protein from solution. Reagents or condition that can cause denaturation are called denaturing agents. Urea is most commonly used as the denaturating agent. Urea may exert its effect directly by making H-bond with polar moieties of the protein, particularly peptide group or indirectly, by altering the solvent environment diminishing the hydrophobic effect. Ex of denaturing agents like :

1.Strong acid or bases

2. Detergents

3. Reducing agent

4. Heavy metal ions

5. Temperature

Some enzymatic amino acids are relatively conserved and can't be changed by any other amino acids, like the catalytic amino acids (at the active site). Histidine, Serine, Tyrosine, Tryptophan etc are some example, removing of which will render the enzyme inactive.

The part of the enzyme where the substrate binds is called the active site. The set of amino acids found in the active site, along with their positions in 3D space, give the active site a very specific size, shape, and chemical behavior. ​If the active site were changed, possibly by a large change in temperature or pH, the enzyme would most likely not be able to catalyze the same reactions. This is because temperature and pH can denature (or change) and enzyme's shape and therefore make it unable to bind with the same specifically shaped substrates as before.​