Anonymous
06-05-2004, 06:54 PM
Question 1: Liver Enzymes Affected By Insulin
Insulin facilitates energy storage in liver. Which enzymes of carbohydrate metabolism are coordinately regulated in liver in response to insulin signalling?
[check all that apply]
Glycogen synthase
Glycogen phosphorylase
phosphofructokinase-1 (PFK-1)
phosphofructokinase-2 (PFK-2)
pyruvate kinase
Insulin Orchestrates Glucose Uptake
http://www.biology.arizona.edu/biochemistry/problem_sets/carbomet/graphics/01t.gif
Six enzymes shown in red (including all five listed in question) are affected by insulin, via three different mechanisms. All but glycogen phosphorylase are stimulated. However, note that PFK-2 is one activity of a bifunctional enzyme - the other "half" of this two-headed beast will come up later in this tutorial.
ans:
Glycogen synthase
Glycogen phosphorylase
phosphofructokinase-1 (PFK-1)
phosphofructokinase-2 (PFK-2)
pyruvate kinase
Yes, all of these enzymes are affected by insulin action. Regulation of all five enzymes can be logically explained as promoting glucose utilization and storage, either in the form of glycogen (liver), fatty acids (adipose tissue) or cholesterol (liver and other peripheral tissues). Intuitively, these processes seem appropriate during times of insulin secretion (i.e., high blood glucose).
Insulin facilitates energy storage in liver. Which enzymes of carbohydrate metabolism are coordinately regulated in liver in response to insulin signalling?
[check all that apply]
Glycogen synthase
Glycogen phosphorylase
phosphofructokinase-1 (PFK-1)
phosphofructokinase-2 (PFK-2)
pyruvate kinase
Insulin Orchestrates Glucose Uptake
http://www.biology.arizona.edu/biochemistry/problem_sets/carbomet/graphics/01t.gif
Six enzymes shown in red (including all five listed in question) are affected by insulin, via three different mechanisms. All but glycogen phosphorylase are stimulated. However, note that PFK-2 is one activity of a bifunctional enzyme - the other "half" of this two-headed beast will come up later in this tutorial.
ans:
Glycogen synthase
Glycogen phosphorylase
phosphofructokinase-1 (PFK-1)
phosphofructokinase-2 (PFK-2)
pyruvate kinase
Yes, all of these enzymes are affected by insulin action. Regulation of all five enzymes can be logically explained as promoting glucose utilization and storage, either in the form of glycogen (liver), fatty acids (adipose tissue) or cholesterol (liver and other peripheral tissues). Intuitively, these processes seem appropriate during times of insulin secretion (i.e., high blood glucose).