An enzyme has two key catalytic residues, Glu 35 (pK_a= 5.9) and Asp 52 (pK_a= 4.5). Which of the following is likely true about the mechanism for this enzyme if the optimum pH = 5.2?

Which of the following mechanisms is not used by enzymes for catalysis?

a) General Acid-base catalysis. 

b) Induced fit of enzyme to transition state. 

c) Destabilizing the transition state. 

d) Providing complementary electrostatics.

e) Binding of metal ions.

f) Specific Acid-Base Catalysis

g) a & c.

h) c & f

i) b, c & f

Which catalytic mechanism uses an electrophilic cofactor to stabilize a negative charge on an intermediate?

Which of the following catalytic mechanisms proceeds via noncovalent interactions?

Suppose that the covalent catalytic mechanism of an enzyme depends on a single active site amino acid (Cys), whose pKa = 8.3. A mutation in a nearby amino acid residue of the enzyme only slightly alters the microenvironment so that the pKa of the Cys residue increases to 10.3. Would this mutation cause the enzyme-catalyzed reaction rate to increase or decrease? Explain.