Abstract: Known cellular transglutaminase is produced as an inactive precursor which is converted to the active species. As described herein, the active species have been identified, cloned, mass produced and purified from bacterial cells. The active transglutaminase herein are useful as a biological glue for, inter alia, adhesive strength in general surgery, clinical orthopedics, skin wound repair, tissue repair, implants, tissue or organ transplantation, stomach and duodenal ulcers, food industry, technical applications, and in applications for cellular apoptosis.