Biology
In competitive inhibition, inhibitor has a shape, charge, size and structure similar to that of the substrate. It therefore competes with the substrate for the active sites to form the enzyme-inhibitor complex (E-I complex) and reduces the number of active sites available for the substrate to bind and form the enzyme-substrate (E-S) complex. If substrate concentration is less than that of competitive inhibitor, it is more likely for the enzyme to collide with the competitive inhibitor and form E-I complex, so rate of product formation will decrease.
Km will increase and there are less number of active sites available for substrate molecules. If substrate concentration is more than that of competitive inhibitor, it is more likely for enzyme to collide with substrate and form E-S complex. The reaction will eventually reach Vmax but only at high substrate concentration. One example of competitive inhibition is where malonate competes with succinate for succinate dehydrogenase.
For non-competitive inhibition, the inhibitors have a structure different from that of the substrate. It binds away from the active site at the allosteric site, inducing conformational change of active site. It prevents substrate from binding to the acgtive site as it is no longer complementary to the shape, orientation, and charge fo the substrate, hence the E-S complex cannot be formed. Km remains constant, affinity does not change. Vmax is lower and there are fewer functional enzymes. for example, cyanide is a non-competitive inhibitor of oxygen to cytochrome oxidase.
- Q: Explain The Effects Of Too High A Temperature On An Enzyme
If the temperature is too high, an increase in kinetic energy of the molecules will cause excessive vibrations of the molecules. This will disrupt the 3 dimensional structure of the enzyme, causing it to become a random coil. The enzyme is therefore denatured....
- #20.factors Affecting The Rate Of Enzyme-catalysed Reactions
These factors are: - Temperature - pH - Enzyme concentration - Substrate concentration - Inhibitor concentration When an enzyme solution is added to a solution of its substrate, the molecules collide. With time, the quantity of substrate...
- #17.2 Enzymes - Syllabus 2016
3.1 Mode of action of enzymes 3.2 Factors that affect enzyme action Enzymes are essential for life to exist. Their mode of action and the factors that affect their activity are explored in this section. Prior...
- #17.1 Enzymes - Syllabus 2015
? Mode of action of enzymes ? Factors that affect enzyme action Learning Outcomes Candidates should be able to: (a) explain that enzymes are globular proteins that catalyse metabolic reactions; (b) explain the mode of action of enzymes in terms of...
- Enzymes
ENZYMES Enzymes are biological catalysts which influence biochemical reactions. All enzymes are proteins but all proteins are not enzymes because there are proteins other than enzymes. Ribozymes: These are the Nucleic acids (RNA) that behave like...
Biology
Enzyme Inhibition
In competitive inhibition, inhibitor has a shape, charge, size and structure similar to that of the substrate. It therefore competes with the substrate for the active sites to form the enzyme-inhibitor complex (E-I complex) and reduces the number of active sites available for the substrate to bind and form the enzyme-substrate (E-S) complex. If substrate concentration is less than that of competitive inhibitor, it is more likely for the enzyme to collide with the competitive inhibitor and form E-I complex, so rate of product formation will decrease.
Km will increase and there are less number of active sites available for substrate molecules. If substrate concentration is more than that of competitive inhibitor, it is more likely for enzyme to collide with substrate and form E-S complex. The reaction will eventually reach Vmax but only at high substrate concentration. One example of competitive inhibition is where malonate competes with succinate for succinate dehydrogenase.
For non-competitive inhibition, the inhibitors have a structure different from that of the substrate. It binds away from the active site at the allosteric site, inducing conformational change of active site. It prevents substrate from binding to the acgtive site as it is no longer complementary to the shape, orientation, and charge fo the substrate, hence the E-S complex cannot be formed. Km remains constant, affinity does not change. Vmax is lower and there are fewer functional enzymes. for example, cyanide is a non-competitive inhibitor of oxygen to cytochrome oxidase.
- Q: Explain The Effects Of Too High A Temperature On An Enzyme
If the temperature is too high, an increase in kinetic energy of the molecules will cause excessive vibrations of the molecules. This will disrupt the 3 dimensional structure of the enzyme, causing it to become a random coil. The enzyme is therefore denatured....
- #20.factors Affecting The Rate Of Enzyme-catalysed Reactions
These factors are: - Temperature - pH - Enzyme concentration - Substrate concentration - Inhibitor concentration When an enzyme solution is added to a solution of its substrate, the molecules collide. With time, the quantity of substrate...
- #17.2 Enzymes - Syllabus 2016
3.1 Mode of action of enzymes 3.2 Factors that affect enzyme action Enzymes are essential for life to exist. Their mode of action and the factors that affect their activity are explored in this section. Prior...
- #17.1 Enzymes - Syllabus 2015
? Mode of action of enzymes ? Factors that affect enzyme action Learning Outcomes Candidates should be able to: (a) explain that enzymes are globular proteins that catalyse metabolic reactions; (b) explain the mode of action of enzymes in terms of...
- Enzymes
ENZYMES Enzymes are biological catalysts which influence biochemical reactions. All enzymes are proteins but all proteins are not enzymes because there are proteins other than enzymes. Ribozymes: These are the Nucleic acids (RNA) that behave like...