Amino Acids

Question 1

Ala

Answer 1

Chosen as a replacement to determine amino acid function for site-directed mutagenesis.

Question 2

Trp

Answer 2

Largest amino acid that can be used to measure protein concentration

Question 3

Pro

Answer 3

Only imino side chain that forces a kink in the polypeptide chains as it bonds the amino group. Cannot hydrogen bond.

Question 4

Gly

Answer 4

Simplest amino acid so it isn’t even chiral!

Question 5

Asn and Gln

Answer 5

Uncharged acidic amino acid that correspond to Asp and Glu, H donors or receptors.

Question 6

His

Answer 6

Imidazole side chain may be positive (protonated) at acidic pH

Question 7

Ser, Thr, and Tyr

Answer 7

Hydroxyl groups that act as nucleophiles in biochemical reactions. Oh groups allow for reversible phosphorylation.

Question 8

Tyr

Answer 8

Derivative of Phe, neurotransmitter precursor. Absorbs light at 280nm.

Question 9

Thr and ile

Answer 9

Have two chiral centers

Question 10

Cysteine residues

Answer 10

Can form disulfide bonds through oxidising the sulfhdryl groups.

Question 11

Intracellular vs extracellular cysteine

Answer 11

Reducing (SH), oxidising (S-S).
In vitro, glutathione acts as an intracellular reducing agent.

Question 12

May also have charged side chains at certain pH???

Answer 12

His and Cys

Question 13

Why proteins are more soluble when carrying a net charge

Answer 13

They repel eachother instead of aggregating