Amino Acids Flashcards
Most AAs are found in the R or S configuration? What are the exceptions?
Most amino acids are S, except cysteine is R and glycine is achiral
Naturally occuring amino acids that play a major role in our body are all in the D or L configuration? What about carbs?
Most are found in the L configuration in eukaryotes and are found in the D configuration in many bacteria while carbs are often found in the D configuration
Which is the simplest amino acid and is achiral?
Glycine, Gly, G
Which amino acid has just a methyl group as a side chain and is often used as the conical example of a simple, small, nonpolar AA?
Alanine. Ala, A
Which amino acids contain isopropyl groups?
Valine, Val, V and Isoleucine, Ile, I
Which amino acid if substituted for glutamic acid in Hb can cause sickle cell disease?
Valine, Val, V
Which are the essential amino acid?
My tall, handsome, vegan friend is watering kale leaves:
- Methionine, Met, M
- Threonine, Thr, T
- Histidine, His, H
- Valine, Val, V
- Phenylalanine, Phe, F
- Isoleucine, Ile, I
- Tryptophan, Trp, W
- Tyrosine, Tyr, K
- Leucine, Leu, L
What are the two sulfur containing amino acids?
Methionine, Met, M and Cysteine, Cys, C
Why is methionine still considered nonpolar?
Bc the only bond sulfur makes is to carbon and the electronegativity difference bt S and C is only 0.3, making it the more inert of the two sulfur containing AAs
Which essential amino acid is found in high quantities in eggs?
Methionine, Met, M
Which amino acid is involved in angiogenesis and DNA methylation?
Methionine, Met, M
What amino acid does the start codon AUG code for?
Methionine, Met, M
What is so unique about proline’s structure?
It is the only AA that has a cyclic component that links back w the AA itself, so the N in the amine group of the back bone is actually part of the proline side chain
What does proline have the ability to do? How does this determine its locations in proteins?
- It introduces proline kinks, which have the ability to break up secondary structures/ motifs and .: the 3D structures formed by the interactions among the amine and carboxylic acids of the AAs
- This is why it is rarely found in the middle of secondary structures like alpha- helices and beta- pleated sheets, but instead it is found at the TURNS of beta pleated sheets
What are the aromatic amino acids? Which one is also an alcohol?
- Phenylalanine, tryptophan, and tyrosine
- Tyrosine is also an alcohol
The presence of what must be controlled in phenylketonuria? What is phenylketonuria?
- Phenylalanine, Phe, F
- A congenital malfunction of the enzyme necessary to convert phenylalanine into tyrosine
What is characteristic of tryptophan’s structure?
Its 2 ring side chain, which contains a benzene rings and a heterocyclic ring containing an amine group
Which AA is a precursor for serotonin and melatonin?
Tryptophan
Why can tyrosine be considered both polar and nonpolar?
It is considered to be amphipathic: The C-OH bond is polar but this is considered to be outweighed by the larger, sterically bulky, hydrophobic ring .: Making the overall behavior more nonpolar. However, the C-OH bond does make it more water soluble than phenylalanine
Which AA is a precursor for many biologically relevant signaling molecules like dopamine, epinephrine, and norepinephrine?
Tyrosine, Tyr, Y
Which AAs contain alcohols making them targets for covalent modifications, ESPECIALLY phosphorylation? Which one is the most commonly phosphorylated?
- Serine, Threonine, and Tyrosine
- Serine, Ser, S
Which of the amino acids containing alcohols has a primary alcohol and which has a secondary alcohol?
Serine has a primary alcohol and threonine has a secondary alcohol
Which amino acids reacts w reducing sugars like fructose and glucose in baked and fried foods to produce the potentially carcinogenic compound, acrylamide?
Asparagine, Asn, N
Which AAs contain amides?
Asparagine, Asn, N and Glutamine, Gln, Q
What is the most common free AA in the blood?
Glutamine, Gln, Q
Which AA is involved in a wide range of metabolic rxns?
Glutamine, Gln, Q
Two cysteine residues can come tg to form what kind of bond? What does this do? How can this bond be broken?
- Two cysteine residues to can come tg to form a disulfide bond and produce cystine
- These bonds help hold tg the tertiary structure of proteins
- These bonds can be broken via reduction to break up the protein’s tertiary structure and reform the individual thiol groups of each cysteine residue
If the electronegativity difference between S and H is only 0.38, why is cysteine still considered a polar amino acid?
Bc it can still participate in H-bonding, although rather weakly
What is a pirate’s favorite amino acid?
Arginine, Arg, R
Which amino acid contains a guanidium group?
Arginine, Arg, R
Which amino acid is the most basic? Why?
Arginine, Arg, R bc the positive charge is resonance stabilized
Which amino acid is involved in the synthesis of several important biomolecules and plays a role in regulating blood pressure?
Arginine, Arg, R
Which basic amino acid is only meaningfully basic?
Histidine, His, H bc ithe deprotonated version of the side chain predominates at physiological pH, making it predominantley uncharged at physiological pH
What is the pKa of the side chain of R? What does this allow it to do?
The pKa of the side chain is 6.04, which allows it to act as a buffer at pH levels slightly more acidic than the physiological pH
Which is the structurally simplest basic amino acid?
Lysine, Lys, K
Which basic amino acid has a primary amine? What does this allow?
Lysine, Lys, K has a fairly reactive primary amine that allows it to serve as a target for methylation and acetylation
What are the positively charged/ basic amino acids?
R, K, H
What are the negatively charged/ basic amino acids?
D,E
Does the protonated or deprotonated form of aspartic acid predominate at physiological pH?
Deprotonated form AKA aspartate
Which amino acid is a structural component in proteins and is an important neurotransmitter?
Glutamic acid/ glutamate
