Question

Explain the effect(s) that the following will have on the use of ketone bodies in the human body (each case is independent)

a. there is a serum albumin deficiency

b. beta-hydroxybutyrate dehydrogenase is inhibited

c. beta-ketoacyl-CoA transferase is inhibited

d. there is a CoA deficiency

e. a compound that is incapable of diffusing into the cell and is highly selective for reactions with ketones (over other carbonyl-containing groups) is released in the bloodstream

Answer 1

A. there is a serum albumin deficiency

Hypoalbuminemia may be a useful marker of ketosis risk, which suggests underlying insulin deficiency. Serum albumin is a sensitive indicator of insulin secretions.

B. beta-hydroxybutyrate dehydrogenase is inhibited

Beta-hydroxybutyrate is a ketone bodies used by the body for energy. Once they reach extra hepatic tissues, beta-hydroxybutyrate is converted to acetoacetate via the enzyme beta-hydroxybutyrate dehydrogenase. Deficiency of this enzyme effects the acetoacetate formation which finally effect the ATP production.

C. beta-ketoacyl-Coo transferase is inhibited

Ketogenesis produces acetone, acetoacetate, and beta-hydroxybutyrate molecules by breaking down fatty acids .Acetoacetate is converted back to acetyl-CoA via the enzyme beta-ketoacyl-CoA transferase. Acetyl-CoA goes through the citric acid cycle, and after oxidative phosphorylation produces 22 ATP per molecule. Beta-ketoacyl-CoA transferase deficiency effect the oxidative phosphorylation

D. there is a CoA deficiency

When two acetyl-CoA molecules lose their -CoAs (or coenzyme A groups), they can form a (covalent) dimer called acetoacetateand the deficiency of enzyme leads to hepatic ketogenesis occurs.

E. a compound that is incapable of diffusing into the cell and is highly selective for reactions with ketones (over other carbonyl-containing groups) is released in the bloodstream

The lack of insulin and corresponding elevation of glucagon leads to increased release of glucose by the liver and the release of free fatty acids from adipose tissue (lipolysis), which are converted through a process called beta oxidation, again in the liver, into ketone bodies (acetoacetate and β-hydroxybutyrate). High glucose levels spill into the urine, taking water and solutes osmotic dieresis occurs.