Inter-alpha-trypsin inhibitors (IαI) are plasma

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

s consisting of three of four heavy chains selected from the group

ITIH1 Inter-alpha-trypsin inhibitor heavy chain H1 is a protein that in humans is encoded by the ''ITIH1'' gene. See also * Inter-alpha-trypsin inhibitor * ITIH2 * ITIH3 * ITIH4 Inter-alpha-trypsin inhibitor heavy chain H4 is a protein that in humans ...

, ITIH2, ITIH3,

ITIH4 Inter-alpha-trypsin inhibitor heavy chain H4 is a protein that in humans is encoded by the ''ITIH4'' gene. See also * Inter-alpha-trypsin inhibitor * ITIH1 * ITIH2 * ITIH3 Inter-alpha-trypsin inhibitor heavy chain H3 is a protein that in humans ...

and one light chain selected from the group AMBP or

SPINT2 Kunitz-type protease inhibitor 2 is an enzyme inhibitor that in humans is encoded by the ''SPINT2'' gene. SPINT2 is a transmembrane protein with two extracellular Kunitz domains to inhibit serine proteases. This gene is a presumed tumor suppressor ...

. They function as

protease A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the ...

inhibitors. IαI form complexes with

hyaluronan Hyaluronic acid (; abbreviated HA; conjugate base hyaluronate), also called hyaluronan, is an anionic, nonsulfated glycosaminoglycan distributed widely throughout connective, epithelial, and neural tissues. It is unique among glycosaminoglycans ...

(HA), generating a serum-derived hyaluronan-associated protein (SHAP)-HA complex. The SHAP-HA complex is found in very high concentration in rheumatoid arthritic

synovial fluid Synovial fluid, also called synovia, elp 1/sup> is a viscous, non-Newtonian fluid found in the cavities of synovial joints. With its egg white–like consistency, the principal role of synovial fluid is to reduce friction between the articular ...

suggesting it has a role in the inflammatory response.

References

External links

* Protease inhibitors Human proteins Arthritis {{protein-stub