Amino Acid Metabolism Quiz

Amino Acid Activators and Transport

• Arginine is an activator of N-acetyl-glutamate synthase
• Glutamine is the form in which ammonia is transported from muscle to the liver

Hepatocyte Activity

• Pericentral hepatocytes express the highest activity of the ornithine cycle enzymes

Amino Acid Contributions

• Tryptophan contributes to the increase in the activity of the sirtuins

Acidosis Effects

• Acidosis increases the activity of glutamine synthesis in the pericentral hepatocytes

Amino Acid Degradation

• Leucine does not contribute to the formation of pyruvate in the course of its degradation

Glucose Synthesis

• Leucine cannot provide any C-atom for the synthesis of glucose in humans

Skeletal Muscle Release

• Alanine and glutamine are released at the highest concentration from skeletal muscle in the fasting state

Glutaminolysis

• Glutaminolysis involves the conversion of glutamine to aspartate

Tetrahydrofolate Transfer

• Serine is the most common source of the 1C groups transferred by tetrahydrofolate

Vitamin Deficiency

• Deficiency of vitamin B12 would cause enhanced excretion of methylmalonate in the urine

Phenylketonuria Diet

• The diet of a patient with phenylketonuria should be enriched with tryptophan and tyrosine

Interconversions

• Glutamic semialdehyde is an intermediate in the interconversion of arginine to proline

Vitamin Co-Factors

• Vitamin C is a co-factor in the synthesis of hydroxyproline

Thyroid Function

• Selenium participates in the structure of deiodinase in the function of the thyroid gland

Nitrogen Balance

• A diet depleted of leucine would lead to a negative nitrogen balance
• A diet depleted of glutamine would have no change in nitrogen balance

Serotonin Sleep-Promoting Effect

• Dietary supplementation with leucine could counteract the sleep-promoting effect of serotonin

Metalloproteases

• Carboxypeptidase is a metalloprotease