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ARS Home » Research » Publications at this Location » Publication #98381
Title: ANIONIC ANTIMICROBIAL PEPTIDES INHIBIT TRYPSIN ACTIVITY

Author
item BROGDEN, KIM
item KALFA, V - VISITING SCI.NADC,AMES,IA

Submitted to: American Society of Microbiologists Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/30/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The respiratory tract is filled with proteolytic enzymes necessary for normal pulmonary metabolism. These include endopeptidases, serine proteases, and surfactant convertases. However, events and inhibitors regulating enzyme activity are unknown. One mechanism utilized in enzymatic regulation is the inhibition of the enzyme by a product of the proteolytic pathway. The lung contains high concentrations of anionic antimicrobial peptides (AP) that may be capable of negative feedback inhibition since their structure is similar to the charge-neutralizing propeptides of Group I serine proteases. The purpose of this study was to assess if AP could neutralize enzymatic activity. In a model system, trypsin was mixed with H-DDDDDDD-OH, H-GDDDDDD-OH, or H-GADDDDD-OH and then incubated with succinylated casein. After 20 minutes, trinitrobenzenesulfonic acid was added to detect unprotected amine groups on digested casein fragments. Significant (P<0.05) inhibition of trypsin activity was seen both when trypsin (1.0 mg/ml) was pre-incubated or co-inc d with AP and succinylated casein. Inhibiting activity varied among AP and H-GADDDDD-OH > H-GDDDDDD-OH > H-DDDDDDD-OH. These results suggest that AP, present in bronchoalveolar lavage fluid, may have a regulatory role in pulmonary metabolism in addition to its innate antimicrobial activity.