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Flashcards in FA synthesis and oxidation Deck (11):

Describe carnitine deficiency

Can't get  LCFAs across mitochondrial membrane, so they build up in cytoplasm; can't use them towards gluconeogenesis or ketogenesis, so you get a hypoketotic hypoglycemia


Which ketone cannot be detected in urine?



Reduced activity of pyruvate carboxylase

Acyl CoA DH deficiency


Elevated dicarboxycyclic acid

Acyl CoA DH deficiency


Describe acyl CoA dehydrogenase deficiency

Class of enzyme that catalyzes first step of FA oxidation in the mitochondria; buildup of dicarboxycyclic acids + hypoketotic hypoglycemia


Acetyl CoA is also a positive regulator of pyruvate carboxyalse in gluconeogenesis, another cause of hypoglycemia in acyl CoA DH deficiency


Elevated LCFA

Carnitine deficiency


Steps in FA oxidation

Cytoplasm = FA + CoA --> acyl CoA --> carnitine shuttle

Mitochondria = Acyl CoA --> breakdown into acetyl CoA groups --> TCA cycle or ketogenesis


Two causes of hypoketotic hypoglycemia

Acyl CoA dehydrogenase deficiency

Carnitine deficiency


Steps in FA synthesis

Citrate in mitochondria --> citrate shuttle across mitochondrial membrane --> citrate in cytoplasm --> ATP citrate lyase --> acetyl CoA --> malonyl CoA --> FA synthesis forms palmitate, a 16C FA


Why does starvation or DKA cause ketoacidosis?

Reduced oxaloacetate = decreased TCA cycle and buildup of acetyl CoA = shunts glucose and FFA towards ketogenesis


Why does alcoholism cause ketoacidosis?

Depletes NADH, which shunts oxaloacetate towards production of malate, causing buildup of acetyl CoA that shunts glucose and FFA towards ketogenesis