Proteases, especially microbial proteases, are widely used in food processing. The purpose of this study was aimed to purify an extracellular protease produced by the strain Staphylococcus simulans QB7 and to evaluate its ability in hydrolyzing meat proteins and generating antioxidant and anti-inflammatory peptides. The optimal conditions for producing the enzyme were as follows: inoculum ratio, 10%; initial pH, 6.5; temperature, 32 °C; incubation time, 36 h; and rotation speed, 160 rpm. The protease had a molecular weight of approximately 47 kDa, possessing the optimal activity at 50 °C, pH 7.0, The protease was stable at pH 4.0–8.0 and 30–60 °C, and the activity was improved by Na+, Mg2+, Ca2+, and Zn2+ ions, whereas it was inhibited by Cu2+, Co2+, Fe3+, Ba2+, Fe2+, β-M, and ethylene diamine tetraacetic acid disodium salt (EDTA). The protease could effectively hydrolyze meat proteins, and the generated hydrolysate could significantly inhibit tumor necrosis factor-alpha (TNFα)-induced oxidative stress, including superoxide and malondialdehyde levels and inflammation (vascular adhesion molecule-1 [VCAM-1] and cyclooxygenase 2 [COX2)) in human vascular EA.hy926 cells. The present findings support the ability of S. simulans QB7 protease in generating antioxidant and anti-inflammatory peptides during the fermentation of meat products.
|State||Published - Jan 2023|
Bibliographical noteFunding Information:
This research was funded by the National Natural Science Foundation of China (No. 32272359 and No. 32060554), the Guizhou Science and Technology Program (QKHPTRC  5004), and the Natural Science and Engineering Research Council of Canada (NSERC, RGPIN-2018-04680). H.L. is the recipient of the scholarship from the China Scholarship Council (202106670005).
© 2022 by the authors.
- microbial extracellular protease
ASJC Scopus subject areas
- Food Science
- Nutrition and Dietetics