The following diagram shows and enzyme (in gray) that has transiently bound cyclic AMP, a signaling molecule (in salmon pink). What kind of bonds/associations are the amino acid side chains in the enzyme (green, blue) forming with the cyclic AMP? Focus only on the bonds/associations indicated by the black arrows.

The investigators reported that the sphingosine kinase enzyme attached to the DEAE column when Tris was used as a buffer, but not when a phosphate buffer at the same pH was used. Explain the difference in behavior. The structure of the conjugate base of the Tris buffer is shown below. Hint: consider what charges all these molecules have at pH 7.4

Starting from the situation below, explain the next immediate steps that occur after the agonist ligand binds to the GPCR. Describe what happens in terms of the GTP and the heterotrimeric G protein structure. www www Ligand α В GTP ZAN Y Copyright ©2009 Pearson Education, Inc. GDP

the following peptide is incubated as chymotrypsin: Gly-Val-Phe-Lys-Ala. Present the detailed chemical mechanism by which chymotrypsin hydrolyzes this peptide. Briefly explain each step. Include only the structure of the final products of the reaction.

(i)  Which graph indicates an enzymatic reaction without inhibitor?(ii)  Which type of inhibitor is it? Briefly explain.(iii)  Which graph indicates the highest concentration of inhibitor?(iv)  Calculate the Vmax and Km of the graph showing an enzymatic reaction with the lowest concentration of inhibitor. Show the steps of calculation and unit in your answers. Keep 2 decimal places in your answers.

Cyclic AMP (CAMP) is an important signaling molecule in cells. The synthesis and degradation of CAMP is diagrammed in the following figure: ATP ©2017 Pearson Education, Inc. 12pt Adenylyl cyclase Edit View Insert Format Tools Table Paragraph Pyrophosphate 3'c- P-P₁ 5'C BI Both caffeine (coffee, cola) and theophylline inhibit the enzyme phosphodiesterase that converts CAMP to AMP, allowing cAMP levels to temporarily remain high. Briefly discuss the possible effect of these drugs on the second messenger action of CAMP. What might the effect of caffeine of theophylline be on a signaling pathway? CAMP UA Phosphodiesterase T² H₂O AMP ⠀

H CH₂ H₂C HC-CH3 CH₂ H H₂C (S) H₂C H CH₂ CH₂ CH₂ NH O C NH NH₂ a) Which of the following statements about this peptide are correct? Group of answer choices Treatment of this peptide with trypsin generates two products. This peptide is a substrate for carboxypeptidase A Treatment of this peptide with cyanogen bromide generates a pentapeptide and a tripeptide. Treatment of this peptide with chymotrypsin generates three products. Treatment of this peptide with elastase generates 2 products. None of the above statements are correct. b) What is the sequence of this peptide using one letter abbreviations? c) What is the pH which would correspond to the ionization of the peptide as drawn above? 1, 5, 7, 10, 14

Which of the following statements are descriptions of metal ion catalysis or examples of metal ion catalysis? Choose all correct answers a Zn²+ cofactor may properly orient the substrate in the active site through ionic interactions. a covalent bond forms between enzyme and substrate lowers the energy or stabilizes the transition state or intermediate catalyst retains its original form after reaction occurs catalysts may participate in oxidation-reduction reactions by changes in the oxidation state

To answer this question, please reference the Problem Solving Video: pH and pK, of an Amino Acid. Proteases are enzymes that cleave peptide bonds using general acid-base catalysis. General acid-base catalysis relies on a protor donor or acceptor other than water. Proteases rely on proton transfer to create strong nucleophiles from active-site amino acid residues. In the protease chymotrypsin, an active-site serine is a potent nucleophile. A nearby residue, His 57, interacts with serine to increase its reactivity. A schematic of chymotrypsin's active site illustrates the active site Ser 195 and His 57 R groups. The Asp 102 residue helps position the His 57 residue via hydrogen bonding. Asp 102 [His] [His+] His 57 6.0 -H-N Chymotrypsin is a digestive enzyme with a catalytic optimum between pH 7.8 and 8.0. However, due to the presence of gastric juice, chymotrypsin often functions in an environment of pH 5.5-7.0. Incorrect The imidazole group of free histidine has a pK₂ of 6.0. Use the…

Noncompetitive inhibition can often be explained by which of the following models? the induced fit model the lock and key model both (a) and (b) neither (a) nor (b)