Lecture 3

Question 1

Amino acid modifications (6)

Answer 1

Acetylation, methylation, phosphorylation, hydroxylation, carboxylation, glycosylation

Question 2

Catecholamine biosynthesis

Answer 2

L-tyrosine –(+OH)–> L-dopa –(-CO2)–> dopamine

–(+OH)–> norepinephrine –(+CH3)–> epinephrine

Question 3

Henderson-Hasselbach equation

Answer 3

pH = pKa + log([A-]/[HA])

Question 4

Interactions integral to protein structure (4)

Answer 4

Electrostatic interaction, hydrogen bonding, hydrophobic interactions, disulfide bonds

Question 5

α-helix

Answer 5

3.6 residues/turn

Formed by hydrogen bonds between 4th NH and 1st C=O

Side chains point outside

Question 6

β-sheet

Answer 6

Pleats = permanent folds

Hydrogen bonds between NH and C=O on adjacent chains

Question 7

Ras protein

Answer 7

Signal transduction protein (molecular “switch”)

Mutation => stays on => numerous cancers

Question 8

Sickle cell anemia

Answer 8

Q6V mutation in β hemoglobin subunit