All living things contain protein catalysts: Enzymes
Lecture Outline
1) Chemical reactions
Rates of chemical reactions : activation energy and transition state
Equilibrium ratio: difference between the energy of product and substrate Exergonic reactions: energy of the product is less than that of the substrate Endergonic reactions: energy of the product is greater than that of the substrate
Equilibrium ratio: difference between the energy of product and substrate
Exergonic reactions: energy of the product is less than that of the substrate
Endergonic reactions: energy of the product is greater than that of the substrate
2) Catalysts
Catalysts accelerate the rate of a reactions by lowering the activation energy Catalysts do not alter the equilibrium ratio of products to substrates
Catalysts accelerate the rate of a reactions by lowering the activation energy
Catalysts do not alter the equilibrium ratio of products to substrates
3) Enzymes
Substrate specificity Substrates into proper orientation and proximity :"tsoo mei" or "marriage brokers" Rates increased many orders of magnitude;
Substrate specificity
Substrates into proper orientation and proximity :"tsoo mei" or "marriage brokers" Rates increased many orders of magnitude;
Turnovers: up to 100,000 reactions per second!
4) Enzymes and coenzymes as "surgical teams"
Active site screens patients for adequate insurance (i.e. substrate specificity). Anesthetize and bind patient (i.e. form an enzyme-substrate complex). Active site groups remove, join, modify or transplant "molecular organs" Coenzyme transplant teams (derived from vitamins) carry the molecular organs between donors and acceptors.
Active site screens patients for adequate insurance (i.e. substrate specificity).
Anesthetize and bind patient (i.e. form an enzyme-substrate complex).
Active site groups remove, join, modify or transplant "molecular organs"
Coenzyme transplant teams (derived from vitamins) carry the molecular organs between donors and acceptors.
"Transplant Team Vitamins"
Thiamin
Riboflavin and Niacin
Pyridoxine
Cyanocobalamin (B12)
Biotin
Folic acid
Pantothenic acid:
5) Evidence for evolution from a common ancestor.
Amino acid sequence differences are consistent with taxonomic relatedness. Common enzyme mechanisms Common use of the same vitamin-derived coenzymes
Amino acid sequence differences are consistent with taxonomic relatedness.
Common enzyme mechanisms
Common use of the same vitamin-derived coenzymes
