We want to measure the activity of alanine aminotransferase (ALAT) present in aserum. The reaction catalyzed by the enzyme is:Reaction 1:I-*H₂N-glutamateH-C-COOCH₂CH₂COO0.1 M phosphate buffer pH 7.4 : 550 μL1.2 M alanine: 100 μLCH3pyruvateCH3Ctime (min)A340CIOOCOOThe enzyme reaction is alized in the following conditions:In a 1 cm-cuvette are added:COO™pyruvatelactate dehydrogenase* (LDH, 300 µμg.mL-¹): 50 μL1.5 mM NADH : 200 μL0.04 M a-ketoglutarate: 500 µLserum containing ALAT: 600 μµLALATNADH + H+00.915a-cétoglutarateCOOLDH* Lactate dehydrogenase (LDH) reduces pyruvate into lactate, with the concomitantoxydation of NADH. This allows to indirectly measure the amount of product formed.с=0CH₂10.741Reaction 2:NAD+CH₂COO™H-CCH3OHCOO™lactatealanineH+ *H3N-CThe reaction is performed at 25 °C and the absorbance at 340 nm is monitored everyminute, for 5 min. The absorbance values are given in the table below:Data:ENADH at 340 nm = 6220 M-¹1.cm-1.One international unit corresponds to the amount of enzyme that catalyzes theconversion of 1 µmole of substrate to product in one minute.320.572 0.402CH340.233COO50.159=Draw the graph A340 f(t). Comment the shape of the curveCalculate alanine, LDH, NADH and a-ketoglutarate concentrations in the reactionmedium at t = 0 (in the same units as the initial concentrations).Calculate the initial rate Vo of the reaction in M.s¹.

If a particular reaction brings about a measurable change (like the generation or consumption of a…

Answered: - Draw the graph A340 = f(t). Comment…

Biochemistry

9th Edition

ISBN:9781319114671

Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Chapter1: Biochemistry: An Evolving Science

Section: Chapter Questions

Problem 1P

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We want to measure the activity of alanine aminotransferase (ALAT) present in a serum. The reaction catalyzed by the enzyme is: Reaction 1: +H3N- glutamate H C CH₂ CH₂ COO -COO + pyruvate CH3 C=0 0.1 M phosphate buffer pH 7.4 : 550 µL 1.2 M alanine : 100 μL CH3 time (min) A340 COO COO™ pyruvate lactate dehydrogenase* (LDH, 300 µg.mL-¹): 50 μL 1.5 mM NADH: 200 μL 0.04 M a-ketoglutarate: 500 μL serum containing ALAT: 600 μL The enzyme reaction is realized in the following conditions: In a 1 cm-cuvette are added: 0 0.915 ALAT NADH + H+ LDH a-cétoglutarate COO * Lactate dehydrogenase (LDH) reduces pyruvate into lactate, with the concomitant oxydation of NADH. This allows to indirectly measure the amount of product formed. Reaction 2: NAD+ 1 0.741 C=O H CH₂ CH₂ COO™ CH3 C-OH COO lactate The reaction is performed at 25 °C and the absorbance at 340 nm is monitored every minute, for 5 min. The absorbance values are given in the table below: Data: alanine ENADH at 340 nm = 6220 M¹.cm1. One…
A certain plant storage protein, after being isolated, was digested using both 8N H2SO4 and conc. Ba(OH)2. The resulting hydrolysates were then analyzed for amino acid composition using paper chromatography with EtOH-NH3-H2O (80:10:10) as the solvent system and ninhydrin as the visualizing agent. Name the amino acids found in the acid hydrolysate labelled 1-5.
Chitinase is a protein that breaks down chitin, a primary component of the cell wall in fungi, scales in fish and exoskeletons of arthropods. The activity of chitinase extracted from a plant was shown to be optimum at pH 5. You were tasked to prepare 300 mL of 150 mM buffer solution for further analysis of the extracted chitinase. REAGENTS Ka 2.5M Acetic acid Solid NaOAc•3H2O [136.08g/mol] 1.76 x 10-5 2.5M NH3 Solid NH4Cl [53.49g/mol] 5.6 x 10-10 2.5M Lactic acid Solid sodium lactate [112.06g/mol] 4.0 x 10-5 5 M HCl 5M NaOH Pls show sol'ns 1. Given the following reagents, give the moles of each component (acid & base).2. What are the mass/volume of the components needed to prepare the buffer? 3. What will the pH of the buffer be if 1mL of 5 M NaOH was added?
The protein catalase catalyzes the reaction 2H,O,(aq) — 2H,O(l) + O,(g) and has a Michaelis-Menten constant of KM = 25 mM and a turnover number of 4.0 × 107 s¯¹. The total enzyme concentration is 0.010 µM and the initial substrate concentration is 4.83 µM. Catalase has a single active site. Calculate the value of Rmax (often written as Vmax) for this enzyme. Rmax Calculate the initial rate, R (often written as V), of this reaction. R = ×10 mM.s-1 mM-s-1
The protein catalase is an enzyme that catalyzes the decomposition of hydrogen peroxide:2 H2O2 (aq) → 2 H2O (l) + O2 (g)and has a Michaelis-Menten constant of 25 × 10-3 mol·dm-3 and a turnover number of 4.0×107s-1.The total enzyme concentration is 0.016×10-6 mol·dm-3 and the initial substrate concentration is4.32×10-6 mol·dm-3 Calculate the maximum reaction rate (????) for this enzyme, and the initial rateof this reaction. Note that catalase has a single active site.
5) In an experiment to investigate the inhibition of the enzyme-glucosidase the following data for the rates of reaction with glucopyranoside for various substrate concentrations was obtained. By constructing a Leaver-Burk plot, determine the value of the Michaelis constant. [S]/ (10-6 mol dm-3) v/ (10-3 mol dm-3 s-1) 1.00 2.00 3.00 4.00 16.7 33.3 41.1 49.8
at what substrate concentration is v= 5.0 mM s^-1 for the enzyme catalyzed hydrolysis of trehalose?
The enzyme lysozyme hydrolyzes glycosidic bonds in peptidoglycan, an oligosaccharide found in bacterial cell walls. The active site of lysozyme contains two amino acid residues essential for catalysis: E35 and D52. Which of the following statements about lysozyme is true? More than one may apply The graph shows the pH-activity profile of lysozyme. 100 50 4. 6. 8. 10 pH Residue E35 exhibits general base catalysis O The pKa of E35 is approximately 4.3 O The pKa of D52 is approximately 4.5 O The optimal activity of lysozyme is approximately 5.2 Residue E35 exhibits covalent catalysis The pka of E35 is approximately 6.1 The pka of D52 is approximately 3.7 Activity (% of maximal)
complete the following mechanism showing the cleavge of the peptide bond for the following cysteine protease reaction. you only need a catalytic dyad for cystein proteases because the pKa of cysteine is low enough (8) and close enough to the pH of 7.4 that is can easily be deprotonated by histidine.
Carbonic anhydrase catalyzes the hydration of CO. CO2 + H2O ¬ H½CO3 The Km of this enzyme for CO, is 1.20×104 µ.M. When [CO,] = 3.60×104 µM, the rate of reaction was 4.50 umol·mL! sec-1 a What is Vmax for this enzyme? umol·mL-!sec-!
The KM values for the reaction of chymotrypsin with two different substrates are given in the table below. Considering this information, which substrate has the lower apparent affinity for the enzyme? Which substrate is likely to give a lower value for Vmax? Substrate N-acetylvaline ethyl ester N-acetyltyrosine ethyl ester KM (M) 8.8 X 10-² 6.6 X 10-4 N-acetylvaline ethyl ester has the lower apparent affinity for the enzyme; it will also likely to give a lower Vmax: N-acetyltyrosine ethyl ester has the lower apparent affinity for the enzyme; it will also likely to give the lower V₁ max. N-acetylvaline ethyl ester has the lower apparent affinity for the enzyme; N- acetyltyrosine ethyl ester is likely to give the lower Vmax: N-acetyltyrosine ethyl ester has the lower apparent affinity for the enzyme; N- acetylvaline will likely to give the lower Vmax. None of the above statements are correct.
Pepsin, a peptidase that hydrolyzes proteins, functions in the stomach at an optimum pH of 1.5–2.0. How is the rate of a pepsin-catalyzed reaction affected by each of thefollowing conditions? increasing the concentration ofproteins changing the pH to0 running the reaction at 0°C using lesspepsin

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- Draw the graph A340 = f(t). Comment the shape of the curve Calculate alanine, LDH, NADH and a-ketoglutarate concentrations in the reaction medium at t = 0 (in the same units as the initial concentrations). Calculate the initial rate V₁ of the reaction in M.s¹.