chitinase activity

Definition

Target type: molecularfunction

Catalysis of the hydrolysis of (1->4)-beta linkages of N-acetyl-D-glucosamine (GlcNAc) polymers of chitin and chitodextrins. [EC:3.2.1.14, GOC:bf, GOC:kah, GOC:pde, PMID:11468293]

Chitinase activity refers to the enzymatic hydrolysis of chitin, a linear polymer of N-acetylglucosamine (GlcNAc) residues that forms the major structural component of the exoskeletons of arthropods, the cell walls of fungi, and the periplasmic space of some bacteria. Chitinases are hydrolases that cleave the β-1,4-glycosidic linkages between GlcNAc units in chitin. This catalytic activity is essential for various biological processes, including:
- **Defense against pathogens:** In many organisms, chitinases play a crucial role in the defense against fungal and bacterial infections. By degrading the chitinous cell walls of these pathogens, chitinases disrupt their structure and prevent their growth.
- **Nutrient recycling:** Chitinases are involved in the breakdown of chitinous material, such as shed exoskeletons and fungal cell walls, releasing GlcNAc monomers that can be used as a source of carbon and nitrogen.
- **Development and morphogenesis:** Chitinases play critical roles in the development and morphogenesis of various organisms, including insects, nematodes, and fungi. For example, chitinases are essential for molting in insects, where they degrade the old chitinous cuticle to allow for the formation of a new one.
- **Symbiotic interactions:** Some organisms, such as plants, have evolved chitinases that interact with beneficial fungi. These chitinases may help to establish and maintain symbiotic relationships, such as mycorrhizal associations.
The molecular mechanism of chitinase activity involves the following steps:
1. **Substrate binding:** Chitinase enzymes bind to the chitin substrate through interactions with the GlcNAc residues.
2. **Hydrolysis:** The active site of the chitinase contains a catalytic residue, typically a glutamate or aspartate, which acts as a nucleophile. This residue attacks the glycosidic bond between two GlcNAc units, breaking the bond and releasing a GlcNAc monomer.
3. **Product release:** After hydrolysis, the chitinase releases the product, a GlcNAc monomer, and the enzyme is ready to bind to another substrate molecule.'
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Proteins (3)

Compounds (9)