Microbial cell membranes and sulfhydryl-containing enzymes

Microbial cell membranes and sulfhydryl-containing enzymes represent a composite target for various broad-spectrum antimicrobial agents, particularly heavy metal compounds and certain antiseptics. The microbial cell membrane is a critical phospholipid bilayer that regulates the transport of nutrients and maintains the structural integrity of the cell (StatPearls, 2023). Sulfhydryl-containing enzymes are proteins that possess essential cysteine residues, which are vital for their catalytic function and overall microbial metabolism (NCBI, 2022). Antimicrobial agents like thimerosal or silver nitrate interact with these targets by disrupting membrane permeability and forming stable mercaptides with enzyme thiol groups, leading to rapid cell death (PubChem, 2024). This multi-target approach provides broad-spectrum activity against bacteria, fungi, and some viruses. However, because human cells also contain similar membrane structures and thiol-dependent enzymes, these agents often exhibit significant toxicity if used systemically. Therefore, they are primarily utilized in topical formulations, disinfectants, or as preservatives in vaccines and ophthalmic solutions (WHO, 2021). The lack of high specificity makes these targets effective against many resistant strains but significantly limits their therapeutic index in clinical practice.

Other names

Bacterial cell membranesFungal cell membranesThiol-containing enzymesCysteine-dependent enzymesMicrobial thiol groups

Antimicrobial agents exert their effects by disrupting the structural integrity of microbial cell membranes, leading to the leakage of essential cytoplasmic contents, and by covalently binding to the sulfhydryl (-SH) groups of essential enzymes, which inactivates them through the formation of stable mercaptides (StatPearls, 2023; NCBI, 2022).