Amino Acids Flashcards
the amino acids most commonly found in nature are termed…
alpha amino acids
which amino acid is the only achiral member of the 20 common amino acids?
and what do the others all exist as?
glycine
L-optical form
what amino acids do bacteria have in their outer coat?
D amino acids
which amino acids are hydrophobic?
- valine
- leucine
- methionine
which amino acids are hard to differentiate and why?
- leucine
- isoleucine
have same mr
…. is the only secondary amino acid
proline
threonine is more… than serine?
hydrophobic
what 2 amino acids are homologues of each other?
asparagine + glutamine
how does tryptophan absorb light better than tyrosine?
has a more extended aromatic system
how many amino acids do oligopeptides contain?
2-10
how many amino acids do polypeptides contain?
10-50
how many residues do proteins usually contain?
50-400 residues
what does aspartame split into?
aspartic acid + phenylalanine
peptide bonds have strong..
resonance
for most peptides what does the delocalisation energy stabilise the molecule by?
75-90 kJ/mol
what conformation do peptides prefer to be in?
planar trans (anti/Z)
what does a red colour indicate?
charged groups at pH 7
cysteine are linked by what bonds?
disulphide bonds
glutathione
natural antioxidant
Glu-Cys-Gly
linked via side chain Glu acid
formed disulphide in presence of oxidising agents
believed to help against ageing + cancer
give examples of some medically important small peptides?
Pain Control:
- leucine enkephalin
- methionine enkephalin
Anti-Inflammatory:
bradykinin
Controls BP:
vasopressin
Induces Labour Milk Prod:
oxytocin
what is insulin made from?
2 chains of AA
linked via disulphide bonds
what is sodium dodecyl sulphate (SDS) used for?
denature proteins into uniform rods
what is movement determined by?
mass, shape + charge
what does PAGE stand for?
polyacrylamide gel electrophoresis
