Enzymes Flashcards
What is the definition of applications of biocatalysis?
Central role of enzymes in interdisciplinary sciences
What is fermentation?
A. synthesis and modification of antibiotics
B. Transformation of defined precursors to a desired target product
C. transformation of raw materials in industrial mixtures
C. Transformation of raw materials (sugar, starch, etc) in industrial mixtures (liquors)
What is biotransformation?
A. synthesis and modification of antibiotics
B. Transformation of defined precursors to a desired target product
C. When life depends on a complex network of chemical reactions
B. Transformation of defined precursors to a desired target product
(environmental friendly processes to treat waste)
What does the pharmaceutical industry do for enzymes?
synthesis and modification of antibiotics
finish the sentence
Enzymes have sites that…
…not only bind another molecules but then catalyze a chemical reaction involving that molecule
Is the binding from binding sites reversible or irreversible?
They are reversible, that means there is an equilibrium between the free and bound ligand
True or False:
Binding sites are not specific for particular ligands
False:
Binding sites are usually very specific for a particular ligand
True or False:
Enzymes are protein catalysts that decrease the rate of reactions with being changed in the process.
FALSE:
Enzymes are protein catalyst that INCREASE the rate of reactions WITHOUT being changed in the process.
Do enzymes reduce or increase the activation energy barriers that block chemical reactions?
They greatly REDUCE
What is the use of activation energy?
A. it is required to catalyze a chemical reaction
B. they help with the binding of ligands
C. it is needed to start chemical reactions
D. it is apart of the energy metabolism
C.
Because chemical reactions are normally blocked, so energy is needed to get them started (Activation energy)
What is a substrate? A. enzyme reactants B. catalyst C. a class of enzymes D. an active site
A. enzyme reactants
What are oxidoreductases?
A. Hydrolyze ATP (Na,K ATPase)
B. catalyze reactions in which one molecule is oxidized while the other is reduced
C. transfer carbon, nitrogen or phosphate containing groups
D. break down proteins by hydrolyzing bonds between amino acids
B. catalyze reactions in which one molecule is oxidized while the other is reduced
(oxidases, reductases, dehydrogenases)
What is the transfer of carbon, nitrogen or phosphate containing groups?
Transferases
What is the name when two molecules ligate in an energy-dependent process?
Ligases
What is the active site considered? A. holoenzymes B. high specificity C. high affinity D. apoenzyme
B. high specificity
What is ATPases?
hydrolyze ATP (NA,K ATPase)
What is the name when catalyze polymerization reactions occur? A. Polymerases B. Proteases C. Lyases D. Kinases
A. polymerases
ex synthesis of DNA and RNA
What is the break down proteins by hydrolyzing bonds between amino acids?
Proteases
What is lyase?
A. Catalyze the cleave of C-K and C-O bonds
B. Catalyze the cleavage of H20 bonds
C. Catalyze the binding of C- and P- groups
D. Catalyze the cleave of C-C, C-S, and C-N bonds
D. Catalyze the cleave of C-C, C-S, and C-N bonds
What are isomerases?
They catalyze the rearrangement of bonds within a single molecule
What is the name that catalyzes the addition of phosphate groups to molecules?
Kinases
protein kinases are very common in physiology
What is synthase?
Synthesize molecules in anabolic reactions by condensing two smaller molecules together (ATP synthase)
What happens when the substrate binds to the enzyme?
An enzyme-substrate complex (ES) is formed
How is EP formed?
Enzyme-Product
ES (enzyme-substrate) causes a conformational change in the enzyme that allows catalysis
What are the properties of enzymes? A. Specificity B. Efficiency C. Presence of cofactors D. Regulation E. Location in the cell F. All of the above G. A, B, D, OR E
F - ALL OF THE ABOVE are properties of enzymes
Is this considered active or inactive?
E + CF
enzyme + cofactor
ACTIVE (holoenzyme)
What does the suffix -ase attach to?
Attaches to the substrate of the reaction – to a ore complete description of the chemical reaction catalyzed
What is the complex molecular machine that facilitates the conversion of S --> P ? A. Binding Protein B. Active Site C. Enzyme catalyze D. The uncatalyzed reaction
B. Active Site
How will changes in substrate and/or enzyme properties be measured in?
In an enzyme assay
absorption of light, viscosity, etc.
What does the Michaelis-Menten equation describe?
How reaction velocity varies with substrate concentration
What are “K1, K-1, K2” considered?
Rate constants
An enzyme combines with its substrate to form what?
ES complex
What does the ES complex yield?
ES complex that yields a product releasing the enzyme
Is the concentration of substrate greater or lower than the concentration of enzyme?
GREATER
What is the initial velocity of the reaction used for?
Used to analyze enzymatic reactions
What is the characteristic of an enzyme and its particular substrate that reflects the affinity of the enzyme for that substrate? A. Specificity B. Viscosity C. Velocity D. Km
D. Km
What is equal to the substrate concentration at which the reaction velocity is 1/2 Vmax?
Km
True or False:
Km does not vary with enzyme concentration.
True!
What is the rate of the reaction that is directly proportional to the enzyme concentration? A. Enzyme concentration B. Reaction catalyze C. Km D. All of the above
A. Enzyme concentration
In the Michaelis-Menten curve, At high concentrations of substrate, what is the velocity of the reaction? A. Vmax B. Zero Order C. First Order D. None
B. Zero Order
What is the plot of initial reaction velocity against concentration?
A. hypobolic curve
B. sigmoidal curve
C. hyperbolic curve
C. Hyperbolic curve
What curve does allosteric enzymes show?
A sigmoidal curve
What are the factors that affect the reaction velocity?
Substrate concentration, temperature, pH, inhibitor (competitive and noncompetitive)
What does the Lineweaver-Burk plot calculate?
Km and Vmax
What will a larger Km reflect in the Michaelis-Menten curve?
reflects a low affinity of enzyme for substrate
A low Km will reflect…
a high affinity of enzyme for substrate
