Amino Acids Flashcards
What amino acids are not found in alpha helices and why?
Proline and Glycine
Proline has a rigid structure. The amide group is contained within a ring structure so unable to hydrogen bond
Glycine is small and very flexible. but also super floppy so not good for alpha-helices
N-linked carbohydrates
Added to asparagine in the ER adds glycan (sugar) Important for structure and function
ketogenic amino acids
can be converted into acetyl CoA and ketone bodies through transamination or deamination
leucine and lysine are the amino acids that are solely ketogenic
form acetoacetate and acetyl CoA
tryptophan, tyrosine, phenylalanine, isoleucine, and threonine are both ketogenic and glucogenic
LIFT WYK (lindsey is freaking tired, watch your krap)
glucogenic amino acids
can be converted into glucose through gluconeogenesis
also form pyruvate, alpha ketoglutarate, succinyl Co-A, fumarate, or oxaloacetate
all amino acids except for leucine and lysine
LIFT WYK are glucogenic and ketogenic
What is required for a glycoprotein or glycolipid to be reduced?
for there to be a free anomeric carbon that can be oxidized
nonreducing cyclic are ketal/acetyl
reducing cyclic are hemiacetyl/hemiketal
What is a conservative mutation for glycine?
Alanine, Valine, Leucine, and Isoleucine
What is a conservative mutation for serine?
threonine
What is a conservative mutation for Asparagine
Glutamine
What is a conservative mutation for Phenylalanine
Tryptophan
What is a conservative mutation for lysine?
arginine
What is a conservative mutation for aspartate
glutamate
acid hydrolysis + heat
will break peptide bonds non specifically
proteolysis
specific cleavage of peptides
occurs with help of enzyme protease
ex: trypsin which is released by the pancreas to help with digestion
what is the molecular weight of amino acids?
110 Da aka 110 g/mol
What is the conversion between Da and g/mol
1:1 ratio
Which amino acids can be phosphorylated?
serine, threonine, and tyrosine
because they all have available OH
this changes them from neutral to negatively charged
Which amino acids can mimic the effects of amino acids that can be phosphorylated?
glutamate (E) and aspartate (D)
what occurs when a solution has a high salt concentration?
NaCl is a neutral salt which can disrupt salt bridges by forming ionic bonds with amino acids
it can also disrupt hydrogen bonding
electrostatic interactions
ionic bonds are noncovalent forces that help maintain the tertiary and quaternary structure of a protein
ubiquitin
targets proteins to proteosome for degradation
usually linked to lysine
ionizable amino acid side chains
K, H, R, E, D, C, Y
are altered as protons are added or removed
K, H, R –> increase PI
E, D, C, Y –> decrease PI
alipathic amino acids
nonpolar and hydrophobic
single, branched, or cyclic (non aromatic) carbon backbone
proline, methionine, alanine, valine, isoleucine, leucine
why isn’t glycine considered an alipathic amino acid?
because glycine is too small
hydrophobicity increases the longer the carbon side chain. Although glycine is non-polar, it only has an H atom as its R Group
protease
breaks apart peptide bonds
hydrolysis reaction - requires water to be added to create carboxylic acid and amine
peptide bonds
group of amino acids strung together and connected via condensation reaction and broken by protease
they have some double bond character because the amide nitrogen has a lone electron pair that allows the peptide bond to exist in 2 resonance structures and therefore has restricted rotation and will be planar
peptide hydrolysis
thermodynamically favorable but kinetically slow without a protease
usually water is added and a protease cleaves the peptide bond into individual amino acids
What amino acids are both glucogenic and ketogenic?
LIFT WYK
leucine, isoleucine, phenylalanine, threonine, tryptophan, tyrosine, lysine
