Rat hair follicle and epidermal transglutaminases. Biochemical and immunochemical isoenzymes.

Epidermal and hair follicle transglutaminases (1,4-alpha-D-glucan: orthophosphate alpha-D-glucosyltransferase EC 2.4.1.1) were differentially isolated and subsequently purified from newborn or 4-5-day-old rats. Both enzymes migrated identically on ion-exchange chromatography but were widely separated by block electrophoresis, with the epidermal enzyme migrating further toward the anode. Each enzyme was finally purified by gel filtration. Epidermal transglutaminase had an apparent molecular weight of 56 000-58 000 in this medium and in gels containing sodium dodecyl sulfate (SDS), while hair follicle transglutaminase had a molecular weight of 52 000-54 000 and was reduced to two apparently identical subunits of a molecular weight of 27 000 by denaturing media. Antiserum specific to each transglutaminase was produced in chickens; when conjugated to fluorescein these antisera localized the enzymes to the granular layer of epidermis and the inner root sheath of follicles, respectively.