On what substrate does the enzyme aldolase act?
Aldolase is a glycolytic enzyme that catalyzes the conversion of fructose 1-6-diphosphate to glyceraldehyde 3-phosphate and dihydroxy-acetone phosphate via the glycolysis metabolic pathway.
What enzyme is deficient in hereditary fructose intolerance?
Essential Fructosuria is characterized by the presence of fructose in the urine after ingesting fructose. It arises as a result of a deficiency of the hepatic enzyme fructokinase and is an autosomal recessive genetic disorder. The disorder is mild and it probably remains undiagnosed in many, many people.
What causes aldolase B deficiency?
Fructose intolerance is an autosomal recessive disease, caused by a genetic defect in fructose 1-phosphate aldolase (aldolase B) in the liver. The symptoms of aldolase B deficiency start when the infant is exposed to fructose.
What is the function of aldolase B?
Aldolase B is responsible for the second step in the metabolism of fructose, which breaks down the molecule fructose-1-phosphate into glyceraldehyde and dihydroxyacetone phosphate. To a lesser degree, aldolase B is also involved in the breakdown of the simple sugar glucose.
What is the substrate of aldolase?
Aldolase is highly specific for its substrate, D-fructose. Composition: The three isozymes (A, B, and C) found in mammals are composed of four identical subunits, each a polypeptide chain of 360 amino acids.
What does fructose-bisphosphate aldolase do?
Fructose-bisphosphate aldolase (EC 4.1. 2.13), often just aldolase, is an enzyme catalyzing a reversible reaction that splits the aldol, fructose 1,6-bisphosphate, into the triose phosphates dihydroxyacetone phosphate (DHAP) and glyceraldehyde 3-phosphate (G3P).
What type of mutation causes hereditary fructose intolerance?
Mutations in the ALDOB gene cause hereditary fructose intolerance. The ALDOB gene provides instructions for making the aldolase B enzyme. This enzyme is found primarily in the liver and is involved in the breakdown (metabolism) of fructose so this sugar can be used as energy.
What is aldolase deficiency?
Aldolase A deficiency, is an autosomal recessive metabolic disorder resulting in a deficiency of the enzyme aldolase A; the enzyme is found predominantly in red blood cells and muscle tissue.
What causes fructose malabsorption?
Fructose malabsorption can be due to many causes that include: imbalance of good and bad bacteria in the gut. high intake of refined and processed foods. preexisting gut issues such as irritable bowel syndrome (IBS)
What is aldolase B deficiency?
Aldolase B deficiency results in phosphate depletion and fructose 1-phosphate accumulation in the liver. Consequently, gluconeogenesis and glycogenolysis are blocked, resulting in inhibition of protein synthesis and subsequent liver failure. Essential fructosuria is caused by a defect in the fructokinase gene.
Why does aldolase B cause hypoglycemia?
In individuals deficient in aldolase B activity, this causes an accumulation of fructose-1-phosphate, leading to subsequent inhibition of both glycolytic and gluconeogenesis pathways, thus causing hypoglycemia in individuals.
What causes hereditary fructose intolerance?