Catalysts that boost the speed of reactions without getting changed or consumed in the reaction, lower the activation energy, are sensitive to changes in pH and temperature, and are specific for a particular reaction
Enzymes are proteins made from amino acids
Enzymes
Do not get changed or consumed by the reaction
Do not alter the equilibrium position
Do not alter the thermodynamics or the reactions heat
Do not alter the overall free energy
Enzyme catalysis
Provides a shortcut to reach the same final destination, but with lower activation energy
Six categories of enzymes
Kinases (add phosphate)
Phosphatases (remove phosphate)
Active site
Specific spatial arrangement where the substrate binds
Allosteric site
Different from the active site, can also bind substances to regulate the enzyme
Enzyme-substrate interaction
1. Substrate binds to active site
2. Enzyme and substrate shapes change to become complementary (induced fit model)
3. Substrate is converted to products
4. Enzyme reverts to original shape
Endergonic reaction
Requires energy for the substrate to bind to the enzyme
Exergonic reaction
No extra energy required for the substrate to leave the enzyme
Cofactors
Relatively small, inorganic, minerals like calcium, magnesium, iron, copper, zinc
Coenzymes
Relatively large, organic, vitamins like B vitamins and vitamins A, D, E, K
Cofactors and coenzymes are present in the cell at low concentrations, but their concentration can be increased as needed
Vitamin B2 is riboflavin and provides FAD, vitamin B3 is niacin and provides NAD
