Peptidylarginine deiminase of the mouse. Distribution, properties, and immunocytochemical localization.

Peptidylarginine deiminase (protein-L-arginine iminohydrolase, EC 3.5.3.15) is widely distributed in various organs of the mouse. Activity in salivary glands, pancreas, and uterus is higher than that in the other organs. In submandibular gland and uterus, sex- and estrous cycle-related differences were observed, respectively. The activity in the submandibular gland from females was approximately four times higher than that in the male. In the uterus, the activity increased in proportion to the hyperplasia of the tissues. Peptidylarginine deiminase from the murine skeletal muscle resembles the enzyme obtained from other animal species with respect to enzymatic and chemical properties. Double immunodiffusion tests and immunoblotting analyses showed that the enzymes present in each murine tissue have the same molecular weight (81,000) and are immunologically indistinguishable. Immunohistochemical analyses of salivary glands and pancreas revealed an intense staining only of the exocrine cells. In uterus, the staining was restricted to the luminal and glandular epithelia of endometrium; the intensity of the staining changed during the course of the estrous cycle. Furthermore, immunoelectron microscopy showed that the enzyme is distributed diffusely in the cytoplasm of the exocrine cell. These observations indicate the general importance of peptidylarginine deiminase, presumably in a cytoplasmic secretory process of the exocrine cells.