Carbon Skeleton Metabolism Flashcards
What are the seven main products into which the carbon skeletons of amino acids are degraded?
- Oxaloacetate
- α-Ketoglutarate
- Pyruvate
- Fumarate
- Acetyl CoA
- Acetoacetyl CoA
- Succinyl CoA
During what conditions can amino acids serve as a primary energy source?
Starvation or prolonged fasting, and in conditions like diabetes mellitus
What is gluconeogenesis?
The process by which the liver and kidneys convert amino acids to glucose, especially during starvation
What are glucogenic amino acids?
Amino acids that degrade into pyruvate or TCA cycle intermediates, contributing to glucose production
What are ketogenic amino acids?
Amino acids that degrade into Acetyl CoA or Acetoacetyl CoA, leading to ketone body formation
What are some specialized products derived from amino acids?
- Porphyrins
- Neurotransmitters
- Hormones
- Purines and Pyrimidines
What role does glycine play in heme synthesis?
Glycine forms heme with succinyl CoA
What is creatine phosphate?
A high-energy compound that helps maintain ATP levels during intense muscle contraction
What are normal serum levels for creatinine?
0.6–1 mg/dL
What is the significance of homocysteine in metabolism?
Elevated homocysteine levels are linked to several diseases including atherosclerosis and Alzheimer’s
What can elevated homocysteine levels result from?
- Deficiencies in enzymes involved in methionine metabolism
- Deficiencies in vitamins B6, B12, and folate
- Methionine-rich diets
What is Maple Syrup Urine Disease (MSUD)?
A disorder caused by a deficiency in the enzyme α-Keto acid dehydrogenase, leading to accumulation of branched-chain amino acids
What is the role of arginine in the urea cycle?
Arginine is cleaved by arginase to produce urea and ornithine
What is nitric oxide (NO) and its function?
A vasodilator produced from arginine, involved in regulating blood flow
What is the result of excessive histamine in the body?
Associated with asthma and allergies
