Lecture 4 Flashcards
(26 cards)
Are amino acids chiral?
Yes
What is the unique factor of each amino acid?
The side chain
What varies the properties of an amino acid?
the side chain
What are the groupings of Amino acids?
Negatively charged
Positively charged
Uncharged
Nonpolar amino acids
What is an important feature of the amino acid Glycine?
It is flexible due to the small side chain
What is an important feature of Proline?
Side chain bonds to main chain making an imino acid and making it rigid
What are one letter abbreviations useful for?
Sequence alignment
Mutations
How are ionisable side chains classified?
By their pKa value
What is the pKa value?
an ionisable group on an amino acid or protein is the pH at which 50% of the group is ionised
What is the pI?
the pH at which the net charge on the amino acid is zero
What is phosphorylation?
addition of a phosphate that controls enzyme activity - like an ON/OFF switch
What does hydroxylation do?
Prevent connective tissue diseases and scurvy. Often involves proline and lysine
where in a protein would you expect to find non-polar amino acid residues?
In the inner part of the protein
What is carboxylation essential for?
blood clotting, often glutamate is involved
What is the bond formed when two cystenines form a covalent bond?
Disulfide bond
What is the bond when two amino acids join together?
A peptide bond
What type of bond is a peptide bond?
Covalent bond
What are three characteristics of a peptide bond?
Planar, trans, dipole
What is the purpose of planar conformation in peptide bond?
maximise the pi bond overlap
a longer chain of amino acids joined together is?
A protein
What is a peptide?
A short stretch of amino acids joined together by peptide bonds
What is the common of amino acids chosen by nature?
L-amino acids
What kind of side chain does cystine have?
Sulphur group
What structures are easily detected under UV?
Aromatic structures
