Localization of a serine proteinase inhibitor, B-43, in the bovine pancreas

• Published in: Histochemistry and cell biology Vol. 110; no. 1; pp. 51 - 56
• Main Authors: Nishibori, M, Nakaya, N, Ohtsuka, A, Murakami, T, Saeki, K
• Format: Journal Article
• Language: English
• Published: Germany Springer Nature B.V 01.07.1998
• Subjects: Acinar cells; Animals; Blotting, Western; Cattle; Cell Nucleus - metabolism; Cell Nucleus - ultrastructure; Chymotrypsin; Cytoplasm; Elastase; Endoplasmic reticulum; Fusion protein; Glutathione transferase; Glutathione Transferase - genetics; Glutathione Transferase - metabolism; Immunohistochemistry; Immunoreactivity; Kallikrein; Localization; Ovalbumin; Pancreas; Pancreas - metabolism; Pancreas - ultrastructure; Proteinase; Recombinant Fusion Proteins - metabolism; Serine; Serine proteinase; Serine proteinase inhibitors; Serine Proteinase Inhibitors - genetics; Serine Proteinase Inhibitors - metabolism; Serpins - metabolism; Trypsin
• ISSN: 0948-6143; 1432-119X
• DOI: 10.1007/s004180050264

B-43, a serine proteinase inhibitor belonging to the ovalbumin branch of the serpin superfamily, was purified and cloned from bovine brain. Since [35S]-labeled B-43 forms SDS-stable complexes with pancreatic serine proteinases, trypsin, alpha-chymotrypsin, and kallikrein, it has been suggested that B-43 is capable of inhibiting these serine proteinases and that B-43 may be present in the pancreas. In the present study, we investigated the localization of B-43 in the bovine pancreas immunohistochemically and examined the effect of B-43 on the amidolytic activities of pancreatic serine proteinases. Strong B-43-like immunoreactivity was localized in acinar cells, especially in the basal sides of the cells where the rough endoplasmic reticulum is located. The nuclei of the subpopulation of acinar cells were also immunoreactive for B-43. The recombinant glutathione S-transferase-B-43 fusion protein inhibited the amidolytic activity of trypsin and, to a lesser extent, alpha-chymotrypsin and kallikrein, but not elastase. These results suggest a role of B-43 in regulating serine proteinases both in the cytoplasm and the nucleus.