Powerpoints - Module 2 Flashcards
What is the role of Ribozymes in intron and tRNA processing?
Gene Therapy
Autocatalytic RNA molecules that can adopt complex tertiary structures like proteins. It does not have proteins and mostly made up of nucleotides.
Ribozymes
A reaction that needs high activation energy for a reaction to occur.
Endergonic Reaction
True or False. Energy release from an exergonic reaction is used to start an endergonic reaction.
True. Endergonic and exergonic reactions are coupled together.
Which of the following is not a characteristic of Biological Catalysis?
A. Temp, pressure pH sensitive
B. Greater specificity (minimal side reactions)
C. Lower reaction rates
D. Capacity for control
C. Higher reaction rates
True or False. Proteins are not subjected to denaturation and can be affected by UV radiation.
False. Subjected to denaturation and cannot be affected by UV radiation (non-nucleotide)
Catabolic enzymes that uses water to cleave linkage (ex. Pacreatic lipase - breaks down triecylglycerol)
Hydrolases
Drug that inhibits pancreatic lipase synthesis of triecylglyceride.
Orlistat (Xenical)
Reaction that facilitates atomic rearrangement within the same molecule (ex. Phosphoglucoisomerase).
Isomerase
Joining two or more chemical together (anabolic) coupled with ATP hydrolysis (Ex. Acetyl-CoA)
Ligase
Splitting a chemical into smaller parts without use of water via elimination (ex. Fructose 1,6-biphosphate aldolase)
Lyase
Transfer of electrons or hydrogen atoms from one molecule to another (ex. Lactic acid dehydrogenase)
Oxidoreductase
Moving a functional group from one molecule to another (ex. Hexokinase)
Transferase
What single bonds is broken down by Hydrolases?
Ester, ether, peptide or glycosidic.
What do you call the site other than the active site of an enzyme?
Allosteric site - can change the configuration of the whole enzyme including the active site
True or False. Urease uses the postulate Lock and Key Model.
True
True or False. Hexokinase undergo a lock and key model.
False. Induce fit model
What consists an active holoenzyme?
Apoenzyme and non-protein co-factor
True or False. Metal ions is an example of a prosthetic group.
True
Most of cofactors that participates in catalysis are derived from
Vitamin B
Coenzyme A comes from what Vitamin B?
Vitamin B5/B3 (Pantothenic Acid)
Deficiency in Vitamin B12 (Cyanocobalamin) will result to.
Megaloblastic anemia
Vitamin B that is important in the synthesis Thymidine?
Folic Acid
Carboxypeptidase cleaves
Carboxy- terminal of proteins
A metal that is important in the stabilization of ATP
Magnesium
What metal is important in neutralizing free radicals converting it to hydrogen peroxide to water?
Mn (Superoxide dismutase)
Vitamin B that increases HDL (high density lipoprotein - good cholesterol)
Vitamin B3 - Niacin
Yes or No. Are the following tetrahydrobiopterin in correct relationship?
Phenylalanin -> Tyrosine Tyrosine -> DOPA Tryptophan -> 5-HO-Tryptophan Arginine -> Citruline + Nitric Oxide Etherlipid -> Aldehyde + Glycerol
Yes
True or False. Magnesium acts as a positive charge shield to orevent the disintegration of ATP
True
True or False. Enzymes form transition states at a HIGHER activation energy thru strategic binding and catalytic residue/cofactors
False. LOWER ACTIVATION ENERGY
The following are reaction mechanisms of enzymes except:
A. Ionic Bonds B. Electronegativity C. Lewis acids/bases D. Non-bonded electrons E. Bond polarity
A. COVALENT bonds
Nucleophiles : attracted to positively charge
___________. : attracted to negatively charge
Electrophiles
Proteases work via covalent or acid-base catalysis, both formung an unstable ________ intermediate.
Tetrahedral
What metal competes with the blood in the body and is use to treat for infection?
Zinc+
What is the catalytic triad forming a charge relay network (passing of electrons)?
Serine (strong nucleophile that attack carbonyl C)
Histidine (accepts proton from Serine)
Aspartatic acid (stabilize protonated histidine)
Inactive enzymes
Zymogens - activated by prteolysis (regulation of enzyme)
Deep, narrow pocket with a negatively charged carboxylate.
Trypsin
Wide hydrophobic pocket complements of aromatic side chains of Phe, Tyr & and aliphatic side chains of Leu & Met.
Chymotrypsin
Enzymes lower the _______ of a reaction that makes them efficient catalyst.
Activation energy
Its change determine the direction and equilibrium states of the reaction but NOT the speed of the reaction.
Free Energy
True or False. Enzymes denature at high temperature so rate falls rapidly.
True
True or False. Heat energy causes less collision between enzyme and substrate.
False. It causes MORE collisions.
Optimum pH for Chymotrypsin?
pH 8
True or False. Optimum pH is related to the ionization of specific amino acid residues that constitute the substrate binding site.
True
Until what temperature range will the rate of enzyme-catalyzed reactions in human that generally doubles with every increase of 10 deg celsius?
45-55 deg Celsius (Q10 = 2)
True or False. In a low substrate concentration, increasing its amount will increase the reaction rate.
True
True or False. In a concentration with high amount of saturated enzyme, a reaction will take place if substrate are added.
False. Reaction WILL NOT take place (zero order kinetics)
Substrate concentration versus reaction rate produces a rectangular _____ curve, plateauing towards enzyme saturation.
Hyperbolic
It denotes a substrate concentration at half the maximal velocity
Michaelis constant km
True or False. Most enzymes in the bidy are at the level of Km (first level).
True
Large kM - _____ substrate affinity in forming products.
LOW
Small Km - ______ substrate affinity in forming a product.
High
A large Km may result from either:
Product is formed rapidly (Large K2) and enzyme-substrate complex dissociates rapidly (Large K1).
It allows precise determination of Km and Vmax at less than saturating concentrations. It will convert the hyperbolic line to a straight line.
Double reciprocal or Lineweaver-Burk
Alternative singe-reciprocal plots.
Eadie-Hofstee and Hanes-Woolf plots
True or False. Km/Vmax corresponds to the slope
True
Used to determine the concentration of enzyme and its relative activity. Use to predict the speed of reactions or catalytic efficiency.
Specific activity - predicts the activity of enzyme (Vmax/Protein)
Turnover number - the larger the number, the faster the reaction (Vmax/mol enzyme)
Catalytic constant - (Vmax/St)
The equation that describes the behavior of enzymes exhibiting cooperativity.
Hill equation
The best measure of catalytic efficiency
Kcat/Km
Clearly show the Vmax and Km
Lineweaver-Burk plot
______ inhibitor are unreactive outside the confines of the enzyme’s active site.
Suicide
______ inhibitors binds to the active site preventing enzyme-substrate complex formation; lineweaver-burk plots intersect at y-axis
Competitive
True or False. In competitive inhibitor, if substrate is increase it can replace the inhibitor.
True
______ inhibitor will not bind to the active site but binds to the allosteric site that changes the shape of the enzyme; lineweaver-burk plots intersect at x-axis
Non-competitive
True or False
Competitive Inhibitor : increase Km, unaffected Vmax
Noncompetitive Inhibitor : unaffected Km, decrease Vmax
True
_____ inhibitor bind to the enzyme-substrate complex lowering both Vmax and Km; lineweaver-burk plots shows no intersection
Uncompetitive inhibitor
