The role of L-histidine in the activation of carbonic anhydrase enzyme : A q uantum mechanica l approch

The carbonic anh ydrase (CA ) comprise a family of ubiquitou s zinc metalloenzyme s that catalyze a very si mple physiological reaction, the inte rconversion between ca rbon dioxide and the bicarbonate io n [۱, ۲]. All known is ozymes of carbonic anhydrase contain a single Zn۲+ ion, w hich is esse ntial for catalytic activity, Figure ۱ . In order to regenerate the catalytically active form, a proton transfer reaction must occur from the water bounded to Zn(II) within the enzym e active sit e to the exte rnal mediu m. In the pr esence of activators, an enzyme/activator complex form, eq ۱.EZn۲+(OH۲) + A( Activator) [EZn۲+(OH۲)/ A] EZn۲+(OH-) + AH+ (۱) In this work, we studied the m echanism of interaction between L-histidine , a s an efficie nt amine activator with active center of CA enzyme by u sing quantum mechanical calculatio ns.

کلیدواژه ها:

Carbonic anhydras ، Activator ، Transition State ، QM calculation