Principles of Metabolic Regulation

What is the primary function of AMP-activated protein kinase (AMPK) in cellular metabolism?

For an allosteric enzyme, what Hill coefficient (nH) corresponds to a 9-fold increase in substrate concentration being required to increase the reaction velocity from 10 percent to 90 percent of Vmax?

How is the liver-specific hexokinase IV (glucokinase) regulated when fructose 6-phosphate levels are high?

What is the distinction between the terms 'metabolic regulation' and 'metabolic control' as used in the chapter?

What is the approximate glucose concentration at which the liver's hexokinase IV (glucokinase) is half-saturated?

What is the effect of fructose 2,6-bisphosphate on phosphofructokinase-1 (PFK-1)?

What is the significance of the enzyme PFK-2/FBPase-2 being bifunctional?

In an experiment using a rat liver homogenate to study glycolysis, what was the determined flux control coefficient (C) for hexokinase?

What is the effect of the hormone glucagon on the cellular level of fructose 2,6-bisphosphate (F26BP) in the liver?

What is the role of xylulose 5-phosphate in regulating carbohydrate and fat metabolism in the liver?

In addition to allosteric inhibition by ATP, how is the liver isozyme (L form) of pyruvate kinase regulated in response to low blood glucose?

What is the function of the transcription factor FOXO1 in metabolic regulation?

What is the role of the Carbohydrate Response Element Binding Protein (ChREBP) in the liver?

How is glycogen phosphorylase a, the active form of the enzyme, allosterically regulated in the liver?

What is the primary mechanism by which insulin activates glycogen synthase?

What is the function of the protein glycogenin in glycogen metabolism?

How does epinephrine signaling lead to glycogen breakdown in muscle?

How does the liver isozyme of glycogen phosphorylase function as a glucose sensor?

What is the role of the glycogen-targeting protein GM in muscle cells?

What is the more accurate term for what has historically been called a 'futile cycle,' such as the one involving PFK-1 and FBPase-1?

Approximately what percentage of the genes in the human genome encode regulatory proteins?

What is a key characteristic of the reactions that serve as control points in metabolic pathways?

Which factor is primarily responsible for holding the phosphofructokinase-1 (PFK-1) reaction far from equilibrium within a hepatocyte?

For the aldolase reaction in heart muscle, what is the approximate mass-action ratio (Q) under in vivo conditions?

What is the most common form of covalent modification used to regulate enzyme activity?

According to Table 15-4, which shows relative changes in adenine nucleotide concentrations, when ATP concentration drops from 5.0 mM to 4.5 mM, what is the resulting percentage increase in AMP concentration?

What effect does a high concentration of citrate have on the activity of phosphofructokinase-1 (PFK-1)?

What is the primary function of the bifunctional enzyme consisting of phosphofructokinase-2 (PFK-2) and fructose 2,6-bisphosphatase (FBPase-2)?

Which hormone stimulates the synthesis of the transcription factor SREBP-1c in the liver?

How does glucose act as a sensor to regulate glycogen breakdown in the liver?

Upon phosphorylation by PKA in response to glucagon, what is the effect on the activities of the bifunctional enzyme PFK-2/FBPase-2?

As shown in Figure 15-18, what is the approximate K(0.5) for fructose 6-phosphate for the enzyme PFK-1 when 0.13 micromolar fructose 2,6-bisphosphate is present?

What are the two immediate effects of insulin in a hepatocyte that lead to the activation of glycogen synthase?

What is the primary role of phosphoprotein phosphatase 1 (PP1) in glycogen metabolism?

In heart muscle, what is the standard free-energy change (delta G prime-degree) in kilojoules per mole for the phosphofructokinase-1 (PFK-1) reaction?

How does the pentose phosphate pathway intermediate, xylulose 5-phosphate, act to stimulate glycolysis and fat synthesis in the liver?

Which transcription factor is responsible for turning on the synthesis of gluconeogenic enzymes like PEP carboxykinase in response to a signal from glucagon?

What is a key regulatory difference between the liver (L form) and muscle (M form) isozymes of pyruvate kinase?

How does ATP function as an allosteric inhibitor of phosphofructokinase-1 (PFK-1)?

What is the primary role of the protein glycogenin in the synthesis of new glycogen particles?

What is the approximate K(0.5) for the substrate fructose 1,6-bisphosphate for the enzyme FBPase-1 in the absence of the inhibitor fructose 2,6-bisphosphate?

What is the role of the delta subunit of phosphorylase b kinase in muscle?

Why is the reaction catalyzed by phosphofructokinase-1 (PFK-1) considered the first 'committed' step in the glycolytic pathway?

Based on the metabolic control analysis of a rat liver extract performing glycolysis, what was the flux control coefficient determined for the enzyme phosphohexose isomerase?

In the biosynthesis of amino acids from aspartate in E. coli, what is the advantage of having three different isozymes for aspartokinase, the first enzyme in the pathway?

What is meant by 'concerted inhibition' in the context of allosteric regulation?

The regulation of the biosynthetic pathway from aspartate to isoleucine, where isoleucine inhibits the enzyme that converts threonine to alpha-ketobutyrate, and threonine in turn inhibits its own formation from aspartate, is an example of what type of regulatory mechanism?

What is the consequence of insulin signaling on the transcription factor FOXO1?

What is the approximate concentration at which glucose is maintained in the blood to ensure homeostasis?

Which of the following best describes the purpose of allosteric regulation of enzymes in metabolic pathways?