Detailed pathway of carbohydrate metabolism. Glucose is transported into the cell to undergo metabolism. If it does not need to be used immediately, it will
be converted to glycogen through the intermediaries glucose-6-phosphate and glucose-1-phosphate for use at a later point in time. In the reverse
reactions, glucose-6-phosphatase (G6PC) will convert glucose-6-phosphate to glucose so that it may enter glycolysis and generate energy. Deficiency of
G6PC will result in excessive storage of glycogen as the body is unable to break down glycogen, leading to hypoglycemia and hepatomegaly, the common
findings seen in glycogen storage disease type I (GSD I). The majority of the steps between glucose and pyruvate are reversible, although they may
require separate enzymatic conversions. In gluconeogenesis, glucose is formed from pyruvate by a series of reactions of which fructose-1,6Source: Metabolic Acidosis in the Newborn, Neonatology: Clinical Practice and Procedures
bisphosphatase (FBP1) is a critical step. Deficiency of this enzyme will result in hypoglycemia and other symptoms. Pyruvate is mostly formed from
Citation:
Cohen RS,
Sunshine P. Neonatology:
Clinical Practice
and Procedures;
2015
Available at:
http://mhmedical.com/
glycolysis and
can beStevenson
convertedDK,
by pyruvate
dehydrogenase
(PDH) to acetyl-CoA
(coenzyme
A) to enter the
tricarboxylic
acid
(TCA) cycle and create
Accessed:
July
31,
2017
energy. Pyruvate can also be converted by pyruvate carboxylase (PC) to oxaloacetate, which is necessary for gluconeogenesis and can help to replenish
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TCA cycle intermediates.
Both McGraw-Hill
PDH and PC Education.
deficiency result
in severe
energy deficiency and lactic acidosis.