Determination of the proteolytic profile in Balaustium murorum (Hermann, 1804) (Acari: Prostigmata: Erythraeidae)

ABSTRACT

Balaustium murorum (Acariformes: Erythraeidae) is a pollen feeder and predatory mite that occasionally causes dermatitis. We sought to determine the protease profile in the whole-mite extract of B. murorum using general and specific substrates as well as inhibitors. The pH profiles using two general substrates, azacasein and haemoglobin, revealed an optimal pH of 6 for both substrates. Specific trypsin inhibitor TLCK showed no influence activity towards BApNA; however, TPCK and AEBSF inhibited chymotrypsin and elastase, respectively. Specific cysteine protease inhibitors Cystatin and E-64 influenced both types of cathepsins B and L, while DTT as a specific activator increased the enzymatic activities. Only aminopeptidase showed significant activity and inhibition using negative control and phenanthroline. Chymotrypsin and elastase had the highest activity at pH of 9–10 and 10, respectively, by using both substrates alone and substrates along with specific inhibitors. Cathepsins B and L had pH optima of 6. Aminopeptidase revealed a broad pH optimum of 5–7 on both substrates HA and HPA alone and substrate along with inhibitor phenanthroline. Finally, different concentrations of each inhibitor were used to find IC50 values of TPCK, AEBSF, cystatin, E-64, DTT and phenanthroline required to inhibit half of enzyme activity.

KEYWORDS:

• Balaustium murorum
• protease
• inhibitor

Acknowledgments

The authors would like to thank the deputy of research and technology of Mazandaran University of Medical Sciences for its financial support of this research (project number: 7219). The research was approved by the ethics committee of the Mazandaran University of Medical Sciences (IR.MAZUMS.REC.1399.7219). Also, we would like to appreciate Dr. Tomas Erban from Crop Research Institute of Czeck republic for his considerable comments on text and explanation of scientific checkpoints.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by the Deputy of Research and Technology of Mazandaran University of Medical Sciences, Sari, Iran [Project Number: 7219].