chitotriosidase-1 (chitinase-1, CHIT1)

Function

• degrades chitin & chitotriose
• role in defense against nematodes & other pathogens
• isoform 3 has no enzymatic activity
• random hydrolysis of N-acetyl-beta-D-glucosaminide 1,4-beta- linkages in chitin & chitodextrins

Compartment

secreted, lysosome (small %)

Alternative splicing

named isoforms=3

Expression

• expressed in spleen, secreted by cultured macrophages

Pathology

• very high plasma levels of CHIT1 are found in patients with Gaucher disease type 1

Polymorphism

• duplication of 24 bp in exon 10 leads to the use of a cryptic splice site
  • the normal splice site is still present, but not used
  • results in production of an inactive protein
• about 6% of the population are deficient for CHIT1 activity
• 35% are carriers & show reduced enzyme levels
• people with CHIT1 deficiency appear perfectly healthy

Laboratory

• chitotriosidase in dried blood spot
• chitotriosidase in serum/plasma

More general terms

• glycosidase (glycoside hydrolase)

Database

• OMIM: https://mirror.omim.org/entry/600031
• UniProt: http://www.uniprot.org/uniprot/Q13231.html