An Enzyme's Active Site Contains an Arginine Residue and a Glutamate

Multiple Choice

An enzyme's active site contains an arginine residue and a glutamate residue with pKa's of 2.9 and 9.1,respectively.Both residues are actively involved in the catalytic mechanism and they are the only two ionizable residues in the active site.What would you expect for the optimum pH of the enzyme?

A) 4.0
B) 6.0
C) 8.0
D) No pH can be determined since the information is irrelevant to the optimum pH.