Matrix metalloproteinase-9 activity in ewes' milk and its relationship to somatic cell counts

The presence and the activity of gelatinase-B/matrix metalloproteinase 9 (MMP-9) in ewes' milk was evaluated with a particular focus on the possible correlation with the somatic cell count (SCC). Forty five individual milk samples obtained from lacaune sheep, previously analysed for SCC with values ranging from 5.0 x 104 to 1.6 x 107 cells mL-1, gave overall gelatinolytic activity between 0.53 +/- 0.05 and 4.53 +/- 0.55 fluorescence units min �1 mg �1 protein. Zymography showed that the variation in the gelatinolytic activity depended on variations in the specific activity of MMP-9; no significant differences in MMP-2 (gelatinaseA) activity were observed. Pearson's correlation calculations gave a fair correlation between the presence of somatic cells and the enzymatic activity. MMP-9 in the context of proteolytic activities related to the presence of somatic cells acquires greater importance taking into account the hydrolytic potential of MMP9 versus casein, evaluated in this study by exploiting a molecular docking approach. (c) 2022 Published by Elsevier Ltd