Lysozyme C (LYZ) (LYZ)

Lysozyme C, commonly referred to as tear lysozyme, is a fundamental component of the innate immune system found in various secretions, most notably human tears, where it constitutes a significant portion of the total protein content [UniProt P61626]. Its primary biological function is to provide antimicrobial protection by enzymatically cleaving the peptidoglycan layer of bacterial cell walls, specifically the beta-1,4-glycosidic bonds between N-acetylmuramic acid and N-acetyl-D-glucosamine [PubMed: 10608923]. In clinical practice, a reduction in tear lysozyme levels is a well-established biomarker for ocular surface disorders such as dry eye syndrome and Sjögren's syndrome [PubMed: 25101614]. Beyond its role as a biomarker, lysozyme itself is utilized as a therapeutic agent (lysozyme chloride) for its anti-inflammatory and anti-infective properties in treating respiratory and inflammatory conditions [PubChem CID 16219478]. Furthermore, mutations in the LYZ gene are associated with hereditary systemic amyloidosis, where the protein misfolds and deposits in tissues [PubMed: 8497324]. The protein also exhibits non-enzymatic activities, including the modulation of the immune response and potential anti-tumor effects [PubMed: 15591001]. Understanding the regulation and activity of tear lysozyme is crucial for developing diagnostic tools and treatments for chronic inflammatory and infectious ocular diseases.

Other names

1,4-beta-N-acetylmuramidase CMuramidaseLZMTear lysozymeRenal amyloidosis protein

Lysozyme catalyzes the hydrolysis of the beta-1,4-glycosidic bond between N-acetylmuramic acid and N-acetyl-D-glucosamine in bacterial peptidoglycan, leading to cell wall degradation and osmotic lysis [PubMed: 10608923].