Chapter 6 - Enzymes Flashcards
(24 cards)
What are oxidoreductases?
Transfer of electrons
Transferases?
Group transfer reactions
Hydrolases?
Hydrolysis reactions
Lyases?
Cleavage of C-C, C-O , C-N
Isomerases?
Transfer groups to yield isometric forms
Ligases?
Formation of C-C , C-S, C-O , C-N by condensation rxns
What is a spontaneous reaction?
Where delta G is negative
How do we determine delta G?
Measure the rates of reactants and products when the reaction has reached equilibrium
What is binding energy?
Free energy released by the formation of weak interactions b/w a complementary enzyme and it’s substrate
What is induced fit?
Enzymes undergo a conformational change when the substrates are bound to the active site.
What is covalent catalysis?
Covalent bond between the enzyme and the substrate changes the reaction pathway
What catalyzes the hydrolysis of a peptide bond?
Serine proteases
What’s the amino acid preference for cleaving chymotrypsin?
Phe, trp, ile, tyr
What’s the amino acid preference for cleaving trypsin?
Lysine, argenine
What’s the amino acid preference for cleaving elastase?
Alanine, glycine, valine, small side chain
pH level affects?
Shape and reactivity
Temperature affects?
Movement of substrates and enzyme
What is Km?
The substrate concentration at which half its active sites are filled
What are the 4 different types of enzyme inhibitors?
Competitive
Uncompetitive
Mixed inhibition / non competitive
Irreversible - covalently binds.
Competitive inhibitors?
Affect the slope but not the y-intercept. Only binds to enzyme at low concentrations of substrate. Binds to active site.
Uncompetitive inhibitors?
Affect the y - intercept. But not the slope. Binds only at infinitely high sub started concentrations. Binds at separate site.
Non competitive inhibitors?
Binds at either very low or very high concentrations, binds to both free enzyme and ES complex. Affects both slope and y-intercept
Mixed inhibitors?
Bind to a separate site.
What are enzymes?
Catalysts, the increase reaction rates in both directions by lowering activation energy.
