3. Triose-phosphate isomerase (TPI) catalyzes the movement of a single proton to interconvert dihy- droxyacetone phosphate and glyceraldehyde 3-phosphate in glycolysis and gluconeogenesis. The enzyme, a dimer of identical subunits that are 248 amino acids in humans, has no cofactors, required metal ions, or cooperativity between subunits. The enzyme is found in all tissues. The value of Kcat/KM - 9.2 x 106 sec-'M-1 is close to the rate constant expected for a diffusion-limited reaction. The mechanism of the proton transfer is illustrated in the diagram below. Glu-165 Glu-165 Glu-165 HR OH 20,PO His-95 His-95 His-95 (а) ing structural formulas and naming enzymes and glycolytic intermediates, the reactions of the payoff phase. Consider only anerobic glycolysis. Remember that each glucose molecule yields two mole- cules of glyceraldehyde-3-phosphate (GAP). Indicate the net yield of ATP and NADH generated through anaerobic glycolysis per glucose molecule. The reaction catalyzed by TPI completes the preparatory phase of glycolysis. Write, us-

3. Triose-phosphate isomerase (TPI) catalyzes the movement of a single proton to interconvert dihy- droxyacetone phosphate and glyceraldehyde 3-phosphate in glycolysis and gluconeogenesis. The enzyme, a dimer of identical subunits that are 248 amino acids in humans, has no cofactors, required metal ions, or cooperativity between subunits. The enzyme is found in all tissues. The value of Kcat/KM - 9.2 x 106 sec-'M-1 is close to the rate constant expected for a diffusion-limited reaction. The mechanism of the proton transfer is illustrated in the diagram below. Glu-165 Glu-165 Glu-165 HR OH 20,PO His-95 His-95 His-95 (а) ing structural formulas and naming enzymes and glycolytic intermediates, the reactions of the payoff phase. Consider only anerobic glycolysis. Remember that each glucose molecule yields two mole- cules of glyceraldehyde-3-phosphate (GAP). Indicate the net yield of ATP and NADH generated through anaerobic glycolysis per glucose molecule. The reaction catalyzed by TPI completes the preparatory phase of glycolysis. Write, us-

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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10) The graph shown below is the pre-steady state data for the serine protease (chymotrypsin) enzyme. Explain how this result suggests the formation of a covalent enzyme intermediate in the active site during the first step in the pathway. 3.0 2.0 1.0 1 3 Time (min) p-Nitrophenol (mol/mol of enzyme) 2.
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Lactate dehydrogenase is a tetramer of MW 134000 g/mole composed of subunits which are equal in size. It is found in the cytoplasm of eukaryotic and prokaryotic cells. Describe the secondary, tertiary and quaternary structures of lactate dehydrogenase.