Human chitotriosidase (CHIT1)

**Human chitotriosidase (CHIT1)** is a lysosomal enzyme and one of only two active human chitinases, the other being acid mammalian chitinase[4]. It hydrolyzes the β(1→4) glycosidic linkages between N-acetyl-D-glucosamine residues in chitin—a polymer present in fungal and parasitic cell walls but not in humans[1][3][4]. The enzyme consists of a catalytic domain and a carbohydrate-binding module (CBM), and is structurally characterized by an elongated active site cleft that can bind long chitin polymers[2][5]. CHIT1 is mainly secreted by activated macrophages and plays a role in the innate immune response against chitin-containing pathogens, such as fungi and some parasites[1][3][5]. The enzyme is highly overexpressed and secreted in several diseases, particularly in type 1 Gaucher disease, making it a recognized biomarker for disease monitoring[2][5]. CHIT1 activity can also be elevated in other lysosomal storage disorders, infections, and some inflammatory conditions[4]. Its mechanism of action involves enzymatic degradation of chitin, and it can be selectively inhibited by molecules such as allosamidin[2][4]. Therapeutic targeting of human chitotriosidase faces safety considerations, as a substantial fraction of the population carries mutations that result in chitotriosidase deficiency; inhibition or genetic deficiency of the enzyme may compromise chitin-related host defenses[4].

Other names

ChitotriosidaseChitotriosidase 1Chitinase 1CHIT1

Enzyme inhibition (chitinase inhibitors bind to the enzyme active site and block chitin degradation)