بررسی فعالیت آنزیم آمینوپپتیداز(CD13) N در افرادی با تیتر بالای آنتی‌بادی ضدبروسلا

 Background and Objective: Aminopeptidases remove the amino acids from the N-terminal of proteins and peptides. Aminopeptidase N (CD13) and leucine aminopeptidase are involved in processing and presentation of pathogens to immune cells. Also, enzyme activity in some viral infection and tumors are high. In this study, the activity of CD13 in serum with high level of brucella antibody was measured. Due to the effect of protein, cortisol, bilirubin, and total antioxidant concentration on enzyme activity, these factors were also measured.   Materials and Methods: In this study, 37 sera with high level of brucella antibody and 30 sera from healthy subjects were collected and enzyme activity was measured by spectrophotometry using L-leucine para-nitro-anilid substrate. Protein concentration was determined by the Bradford method, total antioxidant levels was assessed by spectrophotometry method, cortisol level was measured by ELISA method and total bilirubin was determined by calorimetric method.   Results: CD13 activity was not significantly higher in test group than in healthy subjects and there was no correlation between enzyme activity and antibody titer in test group. But there was a direct positive and significant correlation between enzyme activity and cortisol levels. Also, there was a negative correlation between serum protein level with cortisol, bilirubin, and total antioxidant. Also, there was a positive correlation between bilirubin and total antioxidant in test group.    Conclusion: There were no correlation between brucella antibody titer and CD13 activity. Also, factors such as protein, reducing substances, bilirubin and cortisol did not interfere with the results achieved.