Background The purpose of this study is to observe the diagnostic potential of chromogenic substrate (Benzoyl (DL) Arginine p-nitranilide, BAPNA) for detection of bacterial enzymatic activity in gingival crevicular fluid and saliva of health and disease associated periodontal sites. Methods, Forty patients underwent a clinical periodontal examination and were then classified into 4 groups depending on periodontal index score. The GCF and Saliva samples from each group were the quantitatively evaluated for aminopeptidase activity by using Benzoyl (DL) Arginine p-nitranilide (BAPNA) as substrate., Results, The mean of aminopeptidase level of GCF shows an increase from group I to group IV( These values run in parallel with the values of clinical index i.e., more severe the inflammation, higher the index score, and higher is the aminopeptidase level (with the mean of 0.00032 in group I to 0.06883 in group IV). ,In case of the mean values of aminopeptidase levels of saliva showed an increase from group I to group II and a decrease in group III and group IV., Conclusion, As the severity of disease increases, there is a significant increase in aminopeptidase levels suggesting that there is a direct relationship between aminopeptidase levels in gingival crevicular fluid and periodontitis.

Key Words: Chronic periodontitis, aminopeptidase–biochemical marker, endotoxins, and tissue destruction.