Catalyzes the cross-linking of proteins and the conjugation of polyamines to proteins. L-glutaminyl-[protein] + L-lysyl-[protein] = [protein]-L-lysyl-N(6)-5-L-glutamyl-[protein] + NH4(+) Sold under the name Activa TG by Ajinomoto. It has the ability to cross-link protein molecules present in food without the use of salt or binders. Used to improve some of the physical properties such as firmness, elasticity and moisture retention of food such as meat, poultry and seafood. Belongs to the bacterial TGase family.