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ITIH3

inter-alpha-trypsin inhibitor heavy chain 3
2 disorders 2 susceptibility 3p21.1 gene with protein product
HGNC:6168MonarchNCBI Gene 3699ENSG00000162267UniProt Q06033OMIM 146650

Aliases: H3P.

Normal function · from ai-gene-review (Q06033, commit 79fe13b38970) · AI-generated, not KB evidence

ITIH3 is a secreted plasma glycoprotein processed to inter-alpha-trypsin inhibitor heavy chain H3 (HC3). HC3 is ester-linked through the chondroitin-sulfate chain of bikunin to form pre-alpha-inhibitor; bikunin, rather than HC3, supplies the complex's protease-inhibitor activity. HC2- and TSG-6-dependent transesterification can transfer HC3 from bikunin chondroitin sulfate to hyaluronan, incorporating HC3 into HA-rich extracellular matrices. HC3 also contains a cryptic N-terminal hyaluronan-binding site whose noncovalent activity was exposed by proteolytic fragmentation in vitro.

Provides the noninhibitory HC3 component of plasma pre-alpha-inhibitor and, after HC2- and TSG-6-dependent transesterification, becomes an HA-associated heavy chain incorporated into HA-rich extracellular matrices. An N-terminal noncovalent HA-binding site can be exposed by proteolytic processing, whereas intact mature HC3 did not bind in the direct fragment study.
molecular function: hyaluronic acid binding · directly involved in: hyaluronan metabolic process · locations: extracellular matrix; extracellular region · anatomical locations: blood plasma
In the knowledge base · computed from kb/ at build time

Disorders

Relationship is the entry's genetic[].relationship_type. untyped means the entry has a genetic record for the gene but does not type it; its free-text association is shown instead.

DisorderRelationshipWhere the gene appears
Bipolar Disorder susceptibility
Obsessive-Compulsive Disorder susceptibility

Identity from HGNC (snapshot 2026-10-01). Page layers are described in the gene pages documentation.