Summery

   Bacterial isolate  Proteus mirabilis obtained from burns from Al-imam Ali Hospital in  Sadr City, its identified using vitek diagnosis after that its diagnosis morphological and microscopically to ensure of its purity, Then its cultured in production media Luria broth culture media with addition of urea to prove the extent of its ability to produce  urease, the enzyme was then extracted  by  precipitation bacterial cell by using centrifugation process, and then the  resulting extract was filtered to obtain a pure filtrate representing the crude enzyme, then the enzyme purified through  precipitation with Ammonium sulfate as a first purification step,  ion exchange chromatography and gel filtration,  then  the  enzyme activity was measured  for each purification step. The results of  Urease purification  that  extracted from the isolate of  Proteus mirabilis using ammonium sulfate showed that the specific  activity  was (4.71) unit/mg, and the best  saturation ratio was (60%), the number of purification times and  the enzymatic yield  were 3.5, 14.6%  respectively. And the result of enzyme  purification by dialysis was specific activity (8.1) units/mg  ,the number of purification times  and  the  enzymatic yield were 6, 33% respectively .And the result of enzyme  purification  by  using  Ionic exchange - Cellulose DEAE was  the specific  activity  (12.29) units/mg, the number of purification times  and  the  enzymatic yield were 9.2, 8% respectively .And the result of  purification  of  using  gel filtration Sephadex G-200 show that   the specific  activity  was (15.1) units/mg  and the number of purification times and the enzymatic yield  were 11.27, 14% respectively.

   The optimum conditions for the production of  urease from bacteria were tested at various temperatures and pH The results showed that the best temperature for enzyme production was 35°C and the best pH of the production was 7 and the optimum temperature and  pH were tested for the activity  and stability of  enzyme. The results show that the optimum temperature for enzyme  activity and stability  was 55 ° C and 50 ° C respectively while the optimum pH for enzyme activity  was 7.5 and the optimum pH for the enzyme stability was 7.5, 7.5.                                                                                                                   

    The activity  of  the purified enzyme from the bacteria was evaluated after the gel filtration step by adding various  concentrations ranging from 0.001-0.006 mg/ml of gamma triple iron oxide nanoparticle (γ-Fe₂O₃) which  are  obtained  as standard  in size (20-40)nm , 99% purity,  Results showed that the enzyme activity was 0.39 units/milliliters at a concentration of 0.006 mg/milliliters  while the activity  of the enzyme was 1.3 units/milliliters  at a concentration of 0.001 milligrams/milliliters.

     The concentration of urea in human serum was estimated  by using   standard kit, then comparison result with Urease  that purified from bacteria, and  the  enzyme with gamma iron nanoparticles,  the results  show that there is no significant  differences  in urea concentration  between the results obtained  from standard  kit and enzyme  purified  from bacteria this is due to the efficiency of purified  urease  from bacteria but the results  show that there is significant  differences in urea concentration  of  enzyme with nanoparticles because the inhibition of the  enzyme and loss of  its activity by nanoparticle .