MEH: Protein Metabolism Flashcards
What molecule is used as an estimate of muscle mass?
Creatinine (it is the breakdown product of creatine and creatine phosphate)
What is positive nitrogen balance?
When the intake of protein is greater than the output.
It is a normal state in growth and pregnancy or in an adult recovering from malnutrition.
What is negative nitrogen balance?
When intake is greater than output.
This is never physiologically normal.
Give an example of a ketogenic amino acid.
Lysine
Leucine
Give an example of a glucogenic amino acid.
Alanine
Glycine
Define ketogenic amino acid.
An amino acid this is degraded directly into acetyl-CoA, which is the precursor of ketone bodies.
Define glucogenic amino acid.
An amino acid which is converted into glucose.
What is protein turn over?
The balance between protein synthesis and protein degradation.
What is Cushing syndrome?
A condition wherein there is excessive breakdown of protein due to excess cortisol. It present clinically as weakened skin which leads to striae formation.
What is transamination?
Swapping the amine group of one amino acid for the oxygen on a keto acid.
Name 2 aminotransferase enzymes.
- ALT (Alanine aminotransferase)
2. AST (Aspartate aminotransferase)
What does ALT transfer?
Alanine to glutamate
What does AST convert?
Glutamate to aspartate
What is deamination?
Liberates amino group as free ammonia.
How is toxic ammonia removed?
Converted into urine and then directly excreted in urine.
