Nitrogen Metabolism
Enzyme Kinetics
Enzyme Catalysis
Chymotrypsin Mechanism
Math Practice
100
Amino acids that humans cannot synthesize (list them).
Essential Amino Acids (Valine, Phenylalanine, Tryptophan, Threonine, Isoleucine, Leucine, Methionine, Histidine, and Lysine)
PVT TIM HiLL
Very Hot MILK WTF
100
This variable does not necessarily refer to enzyme affinity for substrate, but rather substrate concentration at which we observe half of the maximum reaction velocity.
Michaelis constant, Km
100
The active site of an enzyme undergoes conformational changes during catalysis to stabilize ______________
Transition State
100
Chymotrypsin cleaves after _______ residues on the __________ side.
Aromatic (Phe, Trp, Tyr); C-terminal
100
Calculate the pO2 necessary in order to get a saturation ([MbxO2]/[Mbtot]) = 0.25
0.33Kd
200
This enzyme is found in the intestine and cleaves one by one on the C terminal side of amino acids.
Carboxypeptidase
200
In the following bimolecular reaction, the units of k are _______.
v=-k[A][B]
[M]-1 x s-1
200
_________ promote catalysis by acting as a template, lewis acid, or a redox reactant.
Metal ions in active site
200
_____ and _____ stabilize the oxyanion in the oxyanion hole.
Serine and Glycine’s amines through hydrogen bonding
200
Using the Michaelis Menten equation, calculate the velocity of a reaction given that Km is equal to the substrate concentration.
½ Vmax
300
The _________ pathway is responsible for intracellular protein turnover, and functions by inducing isoelectric expansion of proteins for proteolysis.
Lysosomal/Phagolysosomal Pathway
300
An assumption of the Michaelis-Menten equation where an enzymatic reaction is constantly flowing through each step; substrate binds instantly to enzyme and there is a constant rate of product formation.
Steady-state assumption
300
Enzymes utilize binding energy to maintain proper ________ and to __________.
Substrate specificity and to stabilize the transition state
300
The acyl-Ser intermediate formed is an example of _______
Covalent catalysis
300
For the sequence of coupled reactions below, the ∆Gsum is _______, and this is overall a(n) ___________ reaction sequence.
A -> C
A->B, ∆G= -50 J/mol
C->B, ∆G=42 J/mol
-92 J/mol; favorable
400
_______ is characterized by acute protein malnutrition, abdominal edema, even if caloric intake is adequate.
Kwashiorkor
400
The best kind of drug inhibitor is one that is _________.
A stable analogue of the transition state.
400
In a metabolic pathway, the ________ enzyme is usually regulated and does not follow _____________.
first enzyme; Michaelis-Menten kinetics
400
This catalytic triad group protonates the amine of the C-terminal product that leaves in step 4.
imidazole of Histidine residue
400
The pka of a common allergy medication, Claritin (Loratidine), is 5.3. What is the percentage of protonated form of Claritin in the intestine? (pH of the intestine is 7.4)
0.788% protonated
500
Amino acids are transported through the brush border from the intestinal lumen to the portal vein of the liver by a symporter. The _______ is responsible for creating a sodium gradient for symport of amino acids and sodium into the brush border.
Active Transporter
500
The following double-reciprocal graph demonstrates _______ inhibition.
Competitive Inhibition
500
In phosphorylation of enzymes, a protein kinase transfers a phosphoryl group from ATP to a ____________ of the targeted enzyme.
Serine, Threonine, or Tyrosine hydroxyl group
500
The conjugate base of this residue causes the oxygen of the Serine residue to become polarized.
Aspartate
500
Given the following polypeptide and pKas below, what is the isoelectric point (pI)?
Gly-Lys-Phe-Asp
pKas:
Gly: 2.3, 9.5
Lys: 2.22, 8.88, 10.53
Phe: 2.2, 9.7
Asp: 2.35, 3.65, 9.6
6.58