Which statement below best describes why the histidine side chain serves as the add base catayst in the reaction mechanism of chymatrypsin, a) The pKi value of the side chain proton is close to physiological pH, therefore Hs is an effective acid and base in the catylatic mechanism of chymctrypsin. b) The side chain of His is the only functional group which can hydrogen bend to the Ser 195 hydroxyl and stablize the active site of the free enzyme. c) The lonized His side chain is an effective nucleophile to catalyze the hydrolysis of the peptide bond. d) The question is fatse, Histidine serves as a covalent catalyst in the mechanism of chymotrypsin. Which of the following statements is false regarding the prodein calmoduin? a) Caimodulin is a smail protein which can bind Ca. b) Caimodulin regulates the antrymatic activily of encymes which require Ca+as a cofactor. c) Caimodulin serves as a regulatory subunit to many enrymes which require Ca+as a cofactor. d) in adetion to Ca+, calmodulin binds other casions such as Zn+2, Na and K+and serves as a regulatery subunit foc enzymes which require thesse cofactors. e) All of the atoove are true. uenow an Which oxygen binding protain below would have the lowest oxygen affinity? a) Myogobin b) Hemoglooin A c) Embryonic hemoglabin d) Fetal hemoglotin