The purpose of a new study published in F1000 Research was to investigate the influence of cervical-vaginal fluid (CVF) pH and inhibitory compounds on the proteolytic activity in the CVF. In this study, fluorogenic substrate screening was utilized; a trypsin-specific activity-based probe (ABP) was used to identify active proteases in CVF. It was observed that serine proteases were among the most abundant proteins in the CVF proteome. Labeling human CVF samples with the trypsin-specific ABP revealed serine proteases transmembrane protein serine 11D and kallikrein-related peptidase 13 as active proteases. Additionally, the proteolytic activity in CVF was identified as highly pH-dependent with an almost absolute inhibition of trypsin-like proteolytic activity at physiological pH levels. Therefore, the findings provided a framework to understand proteolytic activity in CVF. Furthermore, the observations rendered clues for a novel regulatory mechanism in which fluctuations in CVF pH have the potential to control catalytic activity in the lower female reproductive tract.