C485 Review Sheet for Exam III (Fall ’15)
This sheet is intended as a study aid, not a comprehensive list of everything
we covered. This sheet hits the highlights.
Basic Units Covered:
The urea cycle is not on this exam explicitly, but to the extent that it is involved in aa
synthesis and catabolism (arg, ornithine) you need to know it.
Amino Acid degradation
a) degradative pathways for all aromatic amino acids
b) active methyl cycle, methionine and cysteine catabolism and anabolism. SAH
hydrolase mechanism.
c) tetrahydrobiopterin as a cofactor in hydroxylation reactions and basic mechanism
d) role of THF and its various forms of bound carbon (see f below)
Amino acid biosynthesis
a)nitrogen fixation- balanced equation for chemical and biological reactions, nitrogenase
function
b)assimilation of ammonia into glutamine and glutamate
c) difference between essential and nonessential amino acids
d) biosynthesis of all amino acids- be sure you can pinpoint the carbon source (i.e.
precursors) for all amino acids
e) side chain amidation strategies
f) Role and structure of tetrahydrofolate and its alkylated versions
g) Mechanism for PLP-catalyzed reactions we discussed in class- esp decarboxylation,
beta elimination/addition, cleavage of serine, etc
h) Role of TPP in synthesis of branched chain amino acids
i) Use of NAD as a true cofactor (DHQ synthase and SAH hydrolase)
j) Mechanism of tryptophan synthase and indole glycerol 3-P synthase
k) regulation- feedback inhibition, enzyme multiplicity (isozymes), cumulative feedback
inhibition, pathway branching and consequences.
l) use of gln as an ammonia donor
Some mechanisms you should explicitly be thinking about:
1)PLP- beta addition/elimination, decarboxylation, transamination, gamma
addition/elimination.
2)TPP role in branched chain aa synthesis.
3)Amadori rearrangement in try and his biosynthesis
4)Complex NAD dependent transformation (SAH hydrolase and DHQ synthase)
5)Tetrahydrobiopterin and hydroxylation
6)Rearrangement in bcaa biosynthesis
7) try synthase