Chi-Lectins: Forms, Functions and Clinical Applications

摘要: Chitinases (EC.3.2.1.14) hydrolyze the β-1,4-linkages in chitin, an abundant N-acetylglucosamine (GlcNAc) polysaccharide that is a structural component of protective biological matrices invertebrate such as insect exoskeletons and fungal cell walls. cleave chitin contain conserved sequence motif DXXDXDXE, which glutamate catalytic residue. are found species including archaea, bacteria, fungi, plants, animals. On basis homologies, chitinases fall into two groups: families 18 19 glycosyl hydrolases. Members family employ substrate-assisted reaction mechanism (van Aalten et al. 2001), whereas those adopt fold-and-reaction similar to lysozyme (Monzingo 1996), suggesting these evolved independently deal with chitin. The glycoside hydrolase (GH18) ancient gene widely expressed archea, prokaryotes eukaryotes. Since important pathogens like fungi well constituent mammalian diet, dual function for innate immunity food digestion has been envisioned (Suzuki 2002; Boot 2005a). Indeed, human chitotriosidase, enzyme predominantly by phagocytes, fungistatic effect demonstrated Eijk 2005). Several studies have tried link common chitotriosidase deficiency susceptibility infection chitin-containing parasites (Bussink 2006). physiological second chitinase, acidic chitinase (AMCase), attracted considerable attention due report linking protein pathophysiology asthma (Zhu 2004).