An enzyme is known to contain four Cys residues that form two disulfide bonds (and no other Cys residues).
[Note that four Cys residues could randomly form three possible disulfide bond arrangements]
A researcher performs the following sequence of treatments on a sample of this enzyme:

Treatment with high concentrations of mercaptoethanol and urea.
Removal of the mercaptoethanol while keeping the urea concentration high (and avoiding formation of any intermolecular disulfide bonds).
Removal of the urea (returning the sample to the original buffer).

They find that the sample obtained from the final treatment has one third of the activity of the original sample of the enzyme .
Which of the following is the best conclusion from this experiment?

Question

An enzyme is known to contain four Cys residues that form two disulfide bonds (and no other Cys residues). 
 [Note that four Cys residues could randomly form three possible disulfide bond arrangements] 
 A researcher performs the following  sequence of treatments  on a sample of this enzyme: 
 
 Treatment with high concentrations of mercaptoethanol and urea. 
 Removal of the mercaptoethanol while keeping the urea concentration high (and avoiding formation of any intermolecular disulfide bonds). 
 Removal of the urea (returning the sample to the original buffer). 
 
 They find that the sample obtained from the final treatment has  one third of the activity of the original sample of the enzyme . 
 Which of the following is  the best conclusion  from this experiment?

Answer

The disulfide bonds have no effect on the activity of the enzyme.

Answer

The enzyme does not need to be correctly folded to be active.

Answer

The enzyme must have the right combination of disulfide bonds to be active.

Answer

The amino acid sequence of the enzyme defines its three-dimensional fold.

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An enzyme is known to contain four Cys residues that form two disulfide bonds (a...

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