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The kcat/Km of urease in the processing of urea is 1014 times greater than the rate of the uncatalyzed elimination reaction of urea.cite-ref-karplus-5-2[5] There are many reasons for this observation in nature. The proximity of urea to active groups in the active site along with the correct orientation of urea allow hydrolysis to occur rapidly. Urea alone is very stable due to the resonance forms it can adopt. The stability of urea is understood to be due to its resonance energy, which has been estimated at 30–40 kcal/mol.cite-ref-karplus-5-3[5] This is because the zwitterionic resonance forms all donate electrons to the carbonyl carbon making it less of an electrophile making it less reactive to nucleophilic attack.cite-ref-karplus-5-4[5]

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