Have specific shapes, so they don't have the same shape
Named according to their job/activity
Can be measured in a clinical laboratory to look for disease
Functionally are biological catalysts
Biological catalysts
Chemicals that increase the rate of reaction
Are not changed at the end of the reaction (structure not changed)
Do not change the nature of the reaction or final result
Lower the activation enery required
Mechanism of Enzyme Action
Substrates have specific shapes (3-dimensional) to fit into the active sites (lock and key model)
Substrate fits into active sites in enzyme
----all happening inside the cell
Control of Enzyme Activity
The rate of enzyme-catalyzed reaction depends on:
Concentration of the enzyme in the solution
Temperature of the solution in which the reaction is occuring
Ph of the solutiion in which the reaction is occuring
Concentration of coenzymes/cofactors (helpers) in the solution (helps enzymes to be more efficient
Effect of temperature
Rate of reaction increases as temperature increases from 0 C up to 37 C
Reaction rate plateaus, slightly above body temperature (37 C)
Above 37 C reaction rate decreases as the temperature continues to increase
Summary of temperature on enzyme activity
From 0 C reaction rate is very slow, it progressively increases as the temperature increases but them plateaus at 37 C (body temp) and then decreases again as the temperature continues to increase
Effect of pH
Each enzyme exhibits peak activity at narrow pH range (pH optimun)
pH optimum reflects the pH of the body fluid in which the enzyme is found
If pH changed, so is no longer within the enzyme range; reaction will decrease
Summary of pH on enzyme activity
Each enzyme has a pH optimun and an increase or decrease in pH can slow down the reaction time
Enzyme Activation
Enzymes may be produced in an inactive form
Phosphorlation/dephosphorylation (Activation/inactivation of an enzyme)
Metabolic Pathways
Sequence of enzymatic reactions that begins with initial substrate, progesses through intermediates and ends with a final product (like an assembly line)
Thousands of enzymatic reaction within a cell do not occur independently of one another-instead they are all connected and effect one another (like branches on a tree)