3D.1 Without performing a calculation, predict whether the standard entropies of the following reactions are likely to be positive or negative: (a) Ala-Ser-Thr-Lys-Gly-Arg-Ser-trypsin →Ala-Ser-Thr-Lys + Gly-Arg (b) N2(g) +3 H2(g) → 2 NH3(g) (c) ATP (aq) + 2 H₂O(l) → ADP³- (aq) + HPO²¯(aq) + H3O+(aq)

The activity of an enzyme requires a glutamic acid to display its -COOH functional group in the protonated state. Suppose the pK, of the -COOH group is 4.07. (a) Will the enzyme be more active at pH 3.5 or 4.5? Explain. (b) What fraction of the enzymes will be active at pH = 4.07? Explain. (c) At what pH will the enzyme show 78% of maximal activity?

Please answer with positive or negative please in the blanks.

The overall adenylate kinase reaction (2 ADP = AMP + ATP) is a combination of 3 reactions: ATP hydrolysis, pyrophosphate hydrolysis, and ATP formation. Show each step and provide the standard free energy (ΔG°′) for each and the overall reaction. If the adenylate kinase reaction is at equilibrium and intracellular [ATP] = 5 mM and [ADP] = 0.5 mM, calculate the concentration of AMP at pH 7 and 25 °C. Show all work. ATP (ADP+P) = -30.5 kj/mol; ATP (AMP+PP) = -45.6 kj/mol; PP = -19.2 kj/mol

b) The methyl group at the C terminus of aspartame can be cleaved by concentrated sulfuric acid (conc. H₂SO4) to reveal the carboxylic acid (compound 1), which has a pK₂ of 2.43. OH NH₂ OCH3 conc. H₂SO4 OH NH₂ OH Compound 1 The other two pKa values in the molecule are unchanged. It is useful to calculate the isoelectric point (pl) when planning to separate charged species from neutral species with electrophoresis. pKal + PK₂2 2 pl = HINT: i) Calculate the isoelectric point of aspartame. ii) Calculate the isoelectric point of compound 1 and explain your reasoning behind the calculation.

Which of the following combination in each pair is likely to produce more Maillard browning when heated at 95 °C for 4 hours? Explain the chemical basis for your choice. Sucrose + glycine, pH 7.0 vs. glucose + glycine, pH 7.0 Maltose with a dextrose equivalency (DE) of 20 + glycine, pH 9.0 vs. maltose + glycine, pH 9.0 Lactose + glycine, pH 8.0 vs. lactose + glycine, pH 4.0

Question attached

P35.27 Bacteriorhodopsin is a protein found in Halobacterium halobium that converts light energy into a transmembrane proton gradient that is used for ATP synthe- sis. After light is absorbed by the protein, the following initial reaction sequence occurs: ic k1=2.0× 1012 s-1 Br k2=3.3 × 101' s-1 J - → K a. At what time will the maximum concentration of the inter- mediate J occur? ry b. Construct plots of the concentration of each species ver- sus time.

An enzyme catalyzes the hydrolysis of an ester with a certain activity, but this activity is lost in a 3 M urea solution. What is the most likely explanation for the loss of activity? (A) Urea binds to the active site of the enzyme competitively with the substrate. (B) Urea causes the cleavage of the peptide bonds in the enzyme. (C) Urea causes the enzyme to denature and lose its specific three-dimensional shape. (D) Urea reacts with disulfide bonds in the enzyme.

Esterase is an enzyme that catalyzes the hydrolysis of esters. It hydrolyzes esters of L-amino acids more rapidly than esters of d-amino acids. How can this enzyme be used to separate a racemic mixture of amino acids?