Transglutaminase (TGase) is a very important enzyme using in food industry today.This enzyme has been used for improving the functional properties of various proteins including meat,soy,myosin,globulin,casein and whey proteins.Modification of proteins by TGase has attracted great interest from food scientists.TGase from Streptoymces is the only commercial cross-linking enzyme on industrial scale.TGase was found to be secreted as zymogene (Pro-TGase) in Streptoymces,and the activation process has been widely studied before.