Amino Acids Flashcards
Alpha carbon
The carbon adjacent to a carboxyl group
Side chains
Give the properties and functionality to the amino acid
Non polar/ Aliphatic amino acids
- Glycine
- Alanine
- Proline
- Valine
- Leucine
- Isoleucine
Polar/uncharged Amino acids
- Asparagine
- Glutamine
- Serine
- Threonine
Sulfur containing AA
- Methionine
-Cysteine
Charged
- Aspartate (-)
- Glutamate (-)
- Arginine (+)
- Lysine (+)
- Histidine (+)
Which amino acids undergo phosphorylation
Ser tyr thr
Which amino acids undergo Glycolysation
Ser, Thr, Asn
Why is glycine so prevalent in proteins
because its so small
Sickle cell anemia mutation
Valine is inserted into the beta chain and ends up mislocated on the outside of haemoglobin (HbS) but should be in the hydrophobic core
PKU disorder
Caused by deficiency in enzyme that converts phenylalanine into tyrosine leading to a build up of phenylalanine and symptoms include mental deficits, seizures
Disulfide bridges
Two cysteisines can form a disulfide bridge through an oxidation reaction with two sulfur molecules in the polypeptide chains in order to stabilise extracellular proteins
Examples of a protein with disulphide bridges
Human insulin/collagen
Hydrogen bond donor
A Hydrogen atom bonded to an electronegative atom like N or O that can donate a hydrogen atom to form a hydrogen bond with an electronegative atom
Hydrogen bond acceptor
An amino acid side chain that has an atom with a lone pair can accept a hydrogen atom to form a hydrogen bond
Electrophoresis
Used to seperate amino acids and proteins as they bear different charges at a given pH
What does the charge on an amino acid and protein confer
Seperating the AAs and proteins and the buffering properties
How does Electrophoresis work
Seperatres by charges to mass ratio. It is moved through an apparatus that is in a tank of a buffer solution, and the amino acids/proteins are put through a gel and separate on how quickly they move through the gel. Negative electrode at the top and positive electrode to the bottom, the samples race to the positive electrode.
Why do pKas change in value
Due to interactions with neighbouring AAs
Why does histidine act as a good buffer
It can exist substantially in both its ionisation states (His - H+ and His)
Assymetric carbon
A Carbon attached to 4 different groups
Convention of drawing amino acids
Amino on the left carboxyl on the top and R group at the bottom (L isomer the D isomer the amino group is on the right)
What type of isomer occurs in AAs in proteins
L - alpha
Eg of why stereoisomers matter
