Lecture 6: Protein Metabolism Flashcards
What supplies amino acids for the body?
Body turnover (400 g) Diet (100 g) De novo synthesis (variable)
What are the three types of intracellular proteolytic control?
Proteasome: breaks down ubiquinated stuff
Lysosme/Autophagy: in lysosomes at low pH
How do extracellular proteolytic control work?
Inactive zymogens are activated by proteolytic cleavage
- Trypsinogen is activate by enterokinase –> trypsin
- Trypsin then activates other molecules
What are ketogenic amino acids?
Leucine
Lysine
What are ketogenic and glucogenic amino acids?
Isoleucine Tryptophan Tyrosine Threonine Phenylalanine
What are glucogenic amino acids?
Not: Leucine Lysine Isoleucine Tryptophan Tyrosine Threonine Phenylalanine
What is a transaminase reaction?
Transfer amine group to alpha-ketoacid to make an amino acid
What is an important coenzyme for transamination reactions?
PLP (Vit B6 derivative)
What happens in hyperhomocysteinemia and homocystinuria?
Deficiency in B6 (PLP), B12 (cobalamin), and B9 (folic acid)
- Ocular: etopia lentis and high myopia
- Skeletal: limbs grow out of proportion
- CNS: dementia
- Vasculature: stroke, thrombosis
What is Maple Syrup Urine Disease?
Deficiency in Branched alpha keto acid dehydrogenase complex
- Urine smells like maple syrup
- Results in ketoaciduria
- Toxic effects on brain
- thiamine supplements and limit valine, leucine, isoleucine
What is Phenylketonuria?
Deficiency in Phenylalanine hydroxylase OR THB (cofactor)
- Build up of phenylalanine and tyrosine is not made
- musty order
What are some important Tryptophan derivatives?
Trp –> Niacin –> NAD/NADP+
*needs B6 (PLP)
Trp –> Serotonin/Melatonin
*needs B6 (PLP)
What are some important Tyrosine derivatives?
Tyrosine –> Thyroid Hormones
Tyrosine –> Melanin
*needs Copper
Tyrosine –> Dopamine
*needs B6 (PLP)
Tyrosine –> Epi/Norepi
What is an important derivative of Serine?
Acetylcholine
What is an important derivative of Glutamate?
GABA
