Chemistry Flashcards
which of the following does NOT make up the side group of one of the 20 AA?
a. thioester
b. thiol
c. methyl
d. hydroxyl
a. thioester
what is true for an AA to be optically active?
they have to be chiral
which of the AA has does not have the S configuration?
cysteine; the sulfur is relatively heavier in molecular weight
which AA are the basic, positively charged AA @ physiological pH?
arginine, lysine, and histidine
the side chains of which of the following amino acids could participate in a salt bridge bonding interaction?
a. aspartic acid
b. phenylalanine
c. cysteine
d. serine
a. aspartic acid
what is required for side chains of AA to participate in salt bridge bonding?
they have to have a basic and acidic amino acid residue (negative and positive interaction)
why are proline and glycine typically not found in the structure of alpha helices?
because they often destabilize (break down) the local structure
why can aspartic acid and glutamic acid mimic a permanently phosphorylated AA?
…and when is it useful?
their side chains are somewhat bulky, negatively charged group, therefore, can mimic a phosphate in certain situations.
useful when designing a constitutively active version of an enzyme which is normally only activated when phosphorylated..
which AA have aromatic side groups?
tyrosine, phenylalanine, tryptophan, histidine
what does high level of AMP indicate?
energy charge is low and ATP needs to be made
what does AMP inhibit? & what does that mean?
It inhibits fructose-1,6-biphosphatase which in turn keeps fructose-1,6-biphosphate
