Subtilisins, EC 3.4.21.62, are a group of proteinases (serine endoproteinases) produced by Bacillus species, exhibiting broad specificity with a preference for large uncharged residues in the P1 position. They are industrial workhorses: variants are used in detergents, in leather and textile processing, and in food applications such as protein hydrolysis for flavourings and tenderization. Their robustness at alkaline pH and elevated temperature makes them process-friendly, and protein engineering has produced variants tuned for specific duties. In foods, controlled proteolysis with subtilisins modifies texture and releases flavour-active peptides.