SSI protease inhibitor
| SSI | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| |||||||||
In
substrate to the active site. It is found only in bacteria
.
Function
SSI is a protease inhibitor, it prevents enzymes from acting on a substrate. Some SSI's also inhibit trypsin, chymotrypsin and griselysin.[1][2] Commercially, SSI's have huge potential in the commercial market, they help stabilise proteases in products such as laundry detergents to prevent autolysis of biological washing powders.[3] This means that the enzymes in the washing powder are kept in optimum performance.
Structure
SSI is a
binding induces the widening of a channel-like structure, in which hydrophobic side-chains are sandwiched between 2 lobes.[4]
Studies have shown that the loss of the
C-terminal domain reduces the inhibitory effect of the proteins. This implies that the C-terminal domain is responsible for maintaining the correct 3D fold.[5]
Structural similarities between the primary and secondary contact
loops of SSI, and the ovomucoid and pancreatic secretory trypsin inhibitor family suggest evolution of the 2 families from a common ancestor.[4]