ABSTRACT
The designation "transglutaminase" was first used by H. Waelsch and co-workers in 1959. Transglutaminases (TG) catalyze cross-linking of proteins, incorporation of low molecular amines into proteins, and hydrolysis of protein-bound glutamine with the formation of protein-bound glutamate. A cellular enzyme-linked immunoabsorbent assay has been developed for estimating cellular TG in situ using a monoclonal antibody produced against tissue TG. In contrast to the epidermal enzyme, guinea pig hair follicle TG has an apparent molecular weight of only about 27 kdaltons in sodium dodecyl sulfate. The catalytical mechanisms for hair follicle and liver TG are probably identical, although these enzymes are different in other respects. TG and its substrate are present in the granular layer of the epidermis and contribute to the cornified envelope. The inner root sheath and medulla of the hair keratinize in a manner similar to epidermis and contain a hair follicle TG.
