Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Biochem Chapter 6
| Question | Answer |
|---|---|
| What are some characterisitics of enzymes? | Specificity/ function under mild conditions such of temperature and pH/ and accelerate chemical reactions |
| Cofactor | Inorganic Ion (ex. Ca2+) |
| Coenzyme | Organic or Metalloorganic molecule |
| Prosthetic Group | Conenzyme or metal ion tightly bound to a enzyme protien |
| Holoenzyme | Catalytically active enzyme together with cofactor/coenzyme |
| Apoprotein | Protien part of the holoenzyme |
| Active Site | Where substrate binds and reaction occurs |
| Substrate | Molecule bound to the active site and worked upon |
| Simple Enzymatic Reaction Equation | E + S -> ES -> EP -> E + P |
| Ground State | The starting point for either the forward or reverse reaction |
| Standard Conditions | 1 atm/ 298K/ 1 M |
| Standard Energy Change in Biochemical Reactions | pH 7.0 |
| Transition State | The point at which the decay to Substrate or Product is equally possible |
| Activation Energy | Difference in energy between ground state and transition state |
| Rate of Reaction and Ea relationship | Higher Ea = Slower Reaction/ Lower Ea = Faster Reaction |
| Catalysts | Lower Ea |
| Role of Enzymes | Speed up conversion of S -> P and Eq is not affected. Reaction reaches EQ when the rate of reaction speeds up |
| Reaction Intermediates | Transient Chemical Species |
| How is rate determined? | By the rate limiting step (one with the highest Ea) |
| Reaction rates are linked to? | Ea |
| Reaction equilibria is linked to? | Gibbs Free Energy (G) |
| Values of G | Negative = Favorable/ Positive = Not |
| How do enzymes speed up reactions? | Covalent Bond formation between substrate and enzymes functional groups/ non-covalent interactions that form release small amounts of energy that help stabalize interactions . Weak interactions are optimized in the transition state because enzyme site is |
| Binding Energy | Energy dervied from enzyme substrate interaction. Major source of free energy used to lower the Ea of reactions |
| What kind of interactions are the main driving force for enzyme catalysis? | Weak binding interactions (mostly formed in the transition state make the largest contribution) |
| Where does specificty in an enzyme come from? | The binding energy |
| What is specificty dervied from? | Many weak interactions between the enzyme and the substrate |
| Things that need to occur for a reaction to take place | Reduction in entropy/ removal of solvation shell/ distortion of substrates/ proper alignment of catalytic groups on the enzyme |
| How does binding energy overcome the factors needed for a reaction to take place? | Hold substrate in place/ Enzyme-substrate interactions replace most the bonds with water/ Change in conformation induced by weak interactions |
| Induced Fit | Bring specific functional groups into position on the enzyme and allows for more weak interactions to occur as conformational change occurs |
| Catalytic Mechanisms | General Acid-Base/ Covalent/ Metal Ion |
| General Acid-Base Catalysis | Proton transfer mediatedd by other classes of molecules |
| Covalent Catalysis | Transient covalent bond is formed between enzyme and the substrate. An enzyme with a nucleophilic group is used an helps alter the reaction pathway with a lower energy |
| Metal Ion Catalysis | Help orient the substrate for reaction or stabalize a charged reaction transition states and mediate redox reaction |
| Chymotrypsin Catalysis Methods | Covalent Catalysis (Cleavage of Bond and formation of a bond between Ser residue on enzyme and part of the substrate)/ General Acid-Base Catalysis |
| Initial Rate (Vo) | When S is much greater than E in concentration |
| Vmax | Region where substrate increases will not increase the initial rate (essentially when all the enzyme has been saturated with the substrate (ES form)) |
| Pre-Steady State | Period in which ES concentration builds up |
| Steady State | ES remains constant over time |
| Steady-state Kinetics | Analysis of Initial Rates |
| Steady-State Assumption | Rate of formation is equal to rate of breakdown |
| Find Vo | Vo = 1/2Vmax |
| Michaelis Menton Graph | Vo = Y/ S = X |
| Double Reciprocal Plot | 1/Vo = Km/vmax[s] + 1/vmax; Slope = Km/Vmax; Y-intercept = 1/vmax (1/vo = Y; 1/S = X) |
| Reversible Enzyme Inhibition | Competitive inhibitor competes with substrate for the active site of an enzyme. Inhibitor occupies active site of enzyme. |
| Uncompetitive Inhibitor | Binds at a different site than the active site |
| Mixed Inhibitor | Binds to both ES or E |
| pH and Enzyme Activity | Can shift how bonds are formed with the substrate or eliminate bonds that are necessary |
| Function of Chymotrypsin | Cuts bonds adjacent to aromatic amino acids/ Trp/ Phe/ Tyr |
| Zymogen | Inactive Precursor which must be cleaved |
| Methods of Enzyme Regulation | Proteolytic Cleavage/ Phosphorylation/ Proenzymes |
| Proenzymes | Must be cleaved |
Created by:
nikeshhajari
Popular Biochemistry sets