Subtilisinartige

Subtilisinartige, or subtilisin-like proteases, are a broad group of serine proteases that share structural and catalytic features with subtilisin, a well-characterized enzyme from Bacillus subtilis. They constitute the subtilisin/S8 family (MEROPS S8) and occur across bacteria, archaea, fungi, plants and animals. Many subtilisin-like proteases are secreted as extracellular enzymes and are produced as inactive precursors containing a propeptide that assists folding and must be removed for activation.

In terms of structure and mechanism, subtilisinartige enzymes typically have a signal peptide for secretion, a propeptide, and a catalytic domain containing a conserved Ser-His-Asp catalytic triad. The catalytic mechanism features nucleophilic attack by the serine, general base catalysis by histidine, and stabilization by aspartate. The propeptide often acts as an intramolecular chaperone and inhibitor that is displaced during maturation.

Diversity and function vary across lineages. In bacteria, subtilisin-like proteases aid nutrient acquisition by degrading environmental proteins. In plants, subtilisin-like proteases (subtilases) participate in development, defense and processing of peptide hormones. In fungi and animals, related enzymes contribute to digestion or processing of various proteins. Subtilisinartige proteases generally exhibit broad substrate specificity, but their preferences can be shaped by residues surrounding the active site and auxiliary domains.

Industrial and research applications are a hallmark of subtilisinartige proteases. Their activity at alkaline pH and thermostability have made them valuable in laundry detergents and food processing. They are also employed in proteomics, peptide sequencing, and biotechnology, where engineered variants with improved stability, altered pH optima, or tailored substrate specificity are common.

Evolutionary analyses show substantial diversity within the S8 family, driven by gene duplications and occasional domain acquisitions, reflecting adaptation to different environments and biological roles.