Amino Acids Flashcards
(23 cards)
What AAs are non-polar and non-aromatic?
Leucine, Isoleucine, Methionine, Proline, Valine, Alanine, Glycine (7)
What are the negatively charged AAs?
Glutamic Acid and Aspartic Acid
What are the positively charged AAs?
Histidine, Lysine, Arginine
What AAs are nonpolar, aromatics?
Tryptophan, Tyrosine, Phenylalanine
Why are some AAs considered essential?
Because the human body cannot produce them, they must be obtained via diet
What is the fundamental structure of AAs?
Central alpha carbon - glue which hold amino acid together, which is bonded to four groups:
- An amino group
- A carboxyl group
- A hydrogen atom
- A unique side chain
What is an R group?
The varying side chain of an amino aced, that give each one its unique properties - size, polarity, charge and how it interacts with other parts of the body
What is the n-terminus?
The amino group which is usually a base and pronated in the environment of the cell - giving it a positive charge
What is the c-terminus?
Usually a carboxyl group - and acid which is typically depronated in the aqueous environment of the cell, giving it a negative charge
What is a zwiitterion?
Because the uncharged amino acids have a plus one and minus one charge under physiological conditions
Ions cancel out producing a net neutral charge
Explain the concept of “like attracts like”
Hydrophobic and hydrophilic interactions
What are the 5 classifications of AAs?
Non-polar allopathic Non-polar aromatic Polar uncharged Polar basic Polar acidic
What are non-polar alipathic AAs?
R-groups contain non-aromatic hydrocarbon chains
What are non-polar aromatic AAs?
R-groups contain aromatic rings (except for histidine which has an aromatic ring but is basic AA)
What are polar AAs?
Can be either charged or uncharged, as the opposite to non-polar AAs, the polar side groups are very hydrophilic and want to maximize their interactions with other polar molecules such as water, contain atoms capable of hydrogen bonding, typically make up the outside of proteins, also have a negative or positive charge
What is an acidic AA?
Aspartic and glutamic acid
Have a negative charge (aside from one at C terminus) at physiological pH
What is a basic AA?
Lysine and arginine
Have an additional positive charge (aside from one at N terminus) at physiological pH
What are the special properties of glycine and proline?
When added into a protein, they will destabilize/break down local alpha helical secondarystructure
What are the special properties of serine, threonine and tyrosine?
Side groups are most often targets of phosphorylation - addition of negatively charged phosphate to a molecule changing the structure and function
Each one has a hydroxyl functional group
What are the special properties of aspartic and glutamic acid?
Can mimic a permanently phosphorylated functional group
When substituted for serine, threonine or tyrosine - able to mimic presence of phosphate group
Phosphomimetic effect
What are the special properties of cysteine?
Able to produce covalent disulfide bonds with other cysteine residues, holding together the subunits of a polypeptide
What are the special properties of basic and acidic residues?
Can interact to form salt bridges due to their attractive positive and negative charges - they play aw important role in stabilizing proteins
What are the two primary methods for synthesizing AAs in the lab?
Strecker synthesis
Gabriel synthesis
