Question: In a certain prokaryotic organism the gene for the glycolytic
enzyme glucose-6-phosphate isomeras…
In a certain prokaryotic organism the gene for the glycolytic
enzyme glucose-6-phosphate isomerase encodes for a protein with
molecular weight of about 59,950 daltons. This enzyme uses a
glutamate residue as a general acid/base catalyst in the mechanism
of this enzyme. The average molecular weight of an amino acid is
110 daltons.
a) If the codon encoding for the
active site glutamate has a point mutation such that the purine is
replaced with a pyrimidine in the third position of the codon, what
will be the most likely result for the activity of this enzyme?
Why? c. Do you think this mutation will have a greater impact on
the Km, Vmax or both for this enzyme? Why? d. This organism has a
Shine-Dalgarno sequence comparable to the consensus sequence found
in many bacteria – AGGAGGU. There is a strain of this organism that
is viable and can grow on glucose, but it has a mutation in the
Shine-Dalgarno sequence – AGGAGAA. This strain can produce norm
amounts of mRNA, but decreased amounts of the fully functional
enzyme. Explain these observations.
