Amino acids Flashcards
What 2 amino acids are purely ketogenic?
- Leucine
- Lysine
All amino acids except from one have both L and D configurations. What amino acid only has one configuration?
Glycine
What are the 2 main basic amino acids - have a positive charge?
- Arginine (most basic)
- Lysine
- Also histidine, although only slightly so has no net charge at plasma pH
What 2 amino acids are found in histones, which give them a positive charge?
- Arginine
- Lysine
What are the 2 main acdic amino acids, have a negative charge as they donate H+ ions making solutions more acidic?
- Aspartate
- Glutamate
What type of amino acids are commonly found in the lipid bilayer of cell membranes?
Hydrophobic
What amino acids are swapped in sickle cell anemia?
Hydrophilic glutamate substituted for nonpolar/hydrophobic valine
What amino acid has a rigid structure and is found in collagen?
Proline
Are most amino acids glucogenic or ketogenic?
- Glucogenic OR glucogenic and ketogenic
What can ketogenic amino acids not become?
Glucose
What are ketogenic amino acids converted into?
Acetyl CoA
What 2 amino acids are purely ketogenic?
- Lysine
- Leucine
Both essential
What is the 1st step in phenylalanine metabolism?
Phenylalanine
-> Tyrosine
Enzyme: Phenylalanine Hydroxylase
What substance acts as a cofactor for phenylalanine hydroxylase?
Tetrahydrobiopterin (BH4)
What does Tetrahydrobiopterin lose and become when converting Phenylalanine into Tyrosine?
Dihydrobiopterin (BH2)
- Loses 2 Hs
What enzyme and molecule converts Dihydrobiopterin (BH2) back to Tetrahydrobiopterin (BH4)?
Dihydrobiopteridine Reductase
- NADH
What enzyme converts Phenylalanine
-> Tyrosine?
Phenylalanine hydroxylase
What is classic PKU due to?
Phenylalanine hydroxylase deficient
What other than defective Phenylalanine hydroxylase can cause PKU?
Defective / deficient BH4 cofactor
What is the most common inborn error of metabolism?
Penylketonuria
What are the signs/symptoms of PKU?
- Musty smell in urine from phenylalanine metabolites
- CNS symptoms - retardatio, sizures, tremor
- Pale skin, fair hair, blue eyes
Why do those with PKU have pale skin, fair hair, blue eyes?
Lack of tyrosine conversion to melanin
How is pku mainly treated?
Dietary modifactions
- Phenylalanine restricted - synthetic aa mixtures use for food
- Phenylalanine level monitored
- No aspartame
- Need to consume tyrosine
Maternal PKU
Occurs in women w. PKU who consume phenylalanine
- High levels act as a teratogen
- Baby born w. microcephaly, congenital heart defects