Ch. 3: Amino Acids Flashcards
What are the nonpolar hydrophobic amino acids?
valine, alanine, glycine, leucine, isoleucine, proline, methionine, phenylalanine, tryptophan
What are the polar, positively charged, basic amino acids?
histidine, lysine, arginine
What are the polar, negatively charged, acidic amino acids?
aspartate, glutamate
What are the polar, neutral amino acids?
cysteine, asparagine, glutamine, serine, threonine, tyrosine
What are the essential amino acids?
methionine, isoleucine, leucine, lysine, valine, phenylalanine, threonine, tryptophan
What are the conditionally essential amino acids?
glutamine, histidine, arginine
What are the non-essential amino acids?
glycine, proline, serine, tyrosine, aspartate, alanine, asparagine, cysteine, glutamate
Glycine: 4 important functions?
1) collagen: every third position a.a.
2) biosynthesis: porphryns & purines
3) bile acids conjugation
4) neurotransmitter: + or -
Disease associated with glycine?
non-ketotic hyperglycinemia (NKH): Inborn error of glycine degradation, effects CNS ➡️ death
Alanine: important function?
Link between a.a. & CHO metabolism
Valine, leucine, isoleucine: important function?
Stabilize 3D structure (hydrophobic) of polymer
Disease associated with valine, leucine, & isoleucine?
Maple syrup urine disease
Disease associated with phenylalanine?
Phenylketonuria: low levels of phenylalanine hydroxylase ➡️ build up of Phe
What are the 4 hydroxylation reactions that need BH4 as cofactor?
1) Phe ➡️ Tyr
2) Tyr ➡️ L-dopa
3) Trp ➡️ S-hydroxytrp
4) Arg ➡️ NO + citrulline
Tryptophan: important function?
Precursor for serotonin, melatonin, nicotinamide
Methionine: important function?
Methyl group donor (SAM)
Proline: 2 important functions?
1) intro restrictions on folding of polypeptide chain
2) collagen synthesis
What are the 2 important hydroxylases for collagen synthesis? What vitamin is needed for hydroxylase rxn?
Proline & lysine hydroxylase
Vitamin C
Aspartate: important function?
On surface of water-soluble proteins
Glutamate: important function?
+ neurotransmitter in brain
Disease associated with glutamate? Drugs that help treat?
Amyotrophic lateral sclerosis (ALS): glu excitotoxicity
Riluzole & gabapentin (GABA analog)
Gamma-carboxyglutamate: important function? What vitamin is needed for formation?
Blood coagulation & anti-coagulation proteins
Vitamin K
Lysine: 4 important functions?
1) linked to biotin, lipoic acid, retinal
2) collagen synthesis
3) cross links for tensile strength & insolubility in elastin & collagen
4) blood clotting: cross-linking in fibrin
Histidine: 2 important functions?
1) essential for infants & uremia pts
2) precursor for histamine (His - carboxyl group)