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Select the statement that best describes the prevalence in proteins of the two generic amino acids shown below.L&Daa(1).png

An inhibitor binds to the active site of an enzyme and in the process is acted upon by the enzyme to form a stable acyl enzyme compound. Which of the following is most likely to occur?

Cysteine’s side chain thiol is ionizable, where image005601c63e5.gif  and the R represents the rest of the amino acid molecule. Given the pH titration curve of the Cys side chain determine its ionization state at physiological pH (7.4).CyspKa.png

Two inhibitors have equivalent inhibition constants (KI), but inhibitor A is a competitive inhibitor and inhibitor B is a noncompetitive inhibitor. Given that all other parameters for their use as a drug in humans are equivalent, what do you predict their relative efficacy would be in the presence of increasing substrate concentration?

Given the dynamic equilibrium between the T and R states of hemoglobin T   s t a t e k 1 ⇌ k – 1 R   s t a t e Show the relationship between the rate constants that is consistent with the equilibrium of this reaction favoring the T state. Enter . k-1[BLANK-1]k1

Leucine zippers are pairs of α-helices in which the side chains of evenly spaced leucines form extensive contacts. A typical leucine zipper is shown below. Select the type of interaction that helps to stabilize this structure. image009601c63e5.jpg

Select the characteristic that is common to the structures of α-helices and β-sheets.

Determine the stereochemistry of each amino acid in the dipeptide below. Enter D or L. Ax3aSA_peptideStructure.png N-terminal amino acid [BLANK-1] C-terminal amino acid [BLANK-2]

Identify the amino acid that will have a net charge of +1 at pH 7.

Some leukemias can be treated by introducing asparaginase into blood. This enzyme degrades asparagine, which is required for cancer cell growth. The graph below shows vo vs. [S] plots for two different asparaginases. The arrow below the horizontal axis marks the concentration of asparagine in the blood. Select the best enzyme and rationale that explains which will be most effective in removing asparagine in the blood.image016601c63e5.gif