More commonly known as "meat glue".
This stuff has been around since the sixties, used by chains like McDonalds to hold their chicken nuggets together. It is also used to turn finely pulverized surimi into sticks of Krab.
It is a white powder that works by creating a covalent bond between the glutamine and lysine ends of a protein. Or, put simply, it holds meats together.
The most basic application of this chemical would be to take two proteins and bind them together. Shown below are alternating pieces of tuna and scallop.
This is done by rubbing one side of a protein with the powder, firmly pressing the two sections together, and refrigerating overnight.
Example: At WD-50, chef Wylie Dufresne uses transglutaminase to create "shrimp noodles". Shrimps are pureed and mixed with a small amount of meat glue (usually at a ratio of about 10 grams transglutaminase to 1 pound protein). The mixture is extruded through a fine tube into 165 F water (the temperature at which shrimp cooks). Upon hitting the water, the noodles cook, and the result is a pasta made entirely of shrimp.