The activity of the enzyme β-galactosidase produced bywild-type cells grown in media supplemented with different carbon sources is measured. In relative units, thefollowing levels of activity are found:Glucose Lactose Lactose + glucose0 100 1Predict the relative levels of β-galactosidase activity incells grown under similar conditions when the cells arelacI−, lacIS, lacO+, and crp−.

The activity of the enzyme β-galactosidase produced bywild-type cells grown in media supplemented with different carbon sources is measured. In relative units, thefollowing levels of activity are found:Glucose Lactose Lactose + glucose0 100 1Predict the relative levels of β-galactosidase activity incells grown under similar conditions when the cells arelacI−, lacIS, lacO+, and crp−.

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter27: Metabolic Integration And Organ Specialization

Section: Chapter Questions

Problem 20P: Figure 27.3 illustrates the response of R (ATP-regenerating) and U (ATP-utilizing) enzymes to energy...

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When ATP and xylose are added to hexokinase, the enzyme produces a small amount of xylose-5-phosphate along with a large amount of ADP. How does this observation support the induced fit model?
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From the complete oxidation of glucose (glucose → 6CO2), how many total nucleotide triphosphates are yielded (be sure to deduct payback) as part of substrate level phosphorylation?
The M and H subunits of lactate dehydrogenase have very similar sizes and shapes but differ in amino acidcomposition. If the only difference between the two were that theH subunit had a glutamic acid in a position where the M subunithad a serine, how would the five isozymes of LDH separate on electrophoresis using a gel at pH 8.6?
Consider the complete oxidation of one mole of simple TAG containing behenic acid residues (22:0). I. For one mole of the fatty acid residue, determine the following: c. ATP yield obtained from FADH2 coming from the complete β-oxidation of the fatty acid residue d. net ATP yield of ATP in the complete oxidation of the fatty acid residue
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Calculate the Km of the maltase reaction with inhibitor X (If inhibitor X changes maltase activity to a Vo of 0.10 mM per minute when [S] = 0.125 mM, and a Vo of 0.25 mM per minute when [S] = 0.50 mM). 0.10 mM 0.20 mM 0.50 mM 1.0 mM 2.0 mM
The most commonly used biochemical reducing agent is: a) NADH b) NADPH c) FADH2 d) LiALH4 Hexokinase catalyzes: a) conversion of glucose to glucose-6-phosphate b) conversion of glucose-6-phosphate to fructose-6-phosphate c) conversion of fructose-6-phosphate to fructose-1,6-biphosphate d) cleavage of fructose-1,6-biphosphate to glyceraldehyde-3-phosphate and dihydroxyacetone phosphate Which one of these molecules is not found in glycolysis? a) 1,3-biphosphoglycerate b) phosphoenolpyruvate c) pyruvate d) oxaloacetate The major regulatory enzyme of glycolysis is: a) hexokinase b) phosphofructokinase c) aldolase d) triose isomerase NADH is produced at which step in glycolysis? a) conversion of fructose-6-phosphate to fructose-1,6-biphosphate b) cleavage of fructose-1,6-biphosphate to glyceraldehyde-3-phosphate and dihydroxyacetone phosphate c) conversion of glyceraldehyde-3-phosphate to 1,3-biphosphoglycerate d) conversion of phosphoenolpyruvate to…
Calculate the Vmax of the above enzyme (lactase). (the enzyme lactase has a Vo of 0.111111111111 mM per minute when [S] = 1.0 mM, and a Vo of 0.20 mM per minute when [S] = 5.0 mM) 0.125 mM per minute 0.25 mM per minute 0.50 mM per minute 1.25 mM per minute 5.0 mM per minute
Calculate the new Km of the above lactase reaction, with inhibitor X. (inhibitor X changes lactase activity to a Vo of 0.10 mM per minute when [S] = 1.0 mM, and a Vo of 0.133333333333 mM per minute when [S] = 2.0 mM) 0.20 mM 0.50 mM 1.0 mM 2.0 mM 5.0 mM
The Beutler test is used to diagnose GALT (UDP-glucose uridyltransferase) deficiency in infants. Blood from the heel is spotted onto filter paper and the spot is then subjected to an enzyme assay. Galactose 1-phosphate, NADP+ and UDP-glucose are added as substrates to the dried blood. The increase in absorbance at 340nm is measured over time which corresponds to reduction of NADP+ to NADPH . The amount of GALT activity in the blood of patients is therefore measured by stoichiometric relationship to the amount of NADPH produced from NADP+. However, GALT does not directly reduce NADP+ as you can see in the above diagram. Instead, the glucose 1-phosphate product from this reaction is shuttled into the oxidative phase of the pentose phosphate pathway by enzymes also present in RBCs. Which three (or possibly more if you must) enzymes downstream of GALT allow for quantitative correlation of a product of GALT with the appearance of NADPH? What is the stoichiometric relationship…