Immunoelectron microscopical localization of ornithine transcarbamylase in hepatic parenchymal cells of the rat.

The electron microscopical localization of ornithine transcarbamylase in rat liver was investigated by a protein A-gold technique applied to thin sections of Lowicryl K4M- or LR gold-embedded materials and to ultracryosections. Gold particles were exclusively confined to mitochondria of the parenchymal cells but not of sinus-lining cells. In mitochondria, gold particles were present in the matrix and closely associated with the inner membrane. The most intensive labelling was obtained from ultracryosections, while weaker labelling was noted in sections of materials embedded in both Lowicryl K4M and LR gold. The association of the enzyme with the inner membrane was confirmed by quantitative analysis of distribution pattern.