Purification of kallikrein from cat submaxillary gland

Abstract

Cat submaxillary gland has been used in many investigations on kallikrein-kinin system. Though it has not yet been established, the physiological functions of kallikreins in various glands, such as the functional vasodilatation, have been studied mainly in cat submaxillary gland (1, 2, 3). Furthermore, the secretory cells or subcellular distribution has been studied in this gland (4). Meanwhile the isolation of submaxillary kallikrein has not yet been achieved. In a series of investigation on the proteases in the rat submaxillary gland, Ekfors, et al. obtained a kallikrein-like peptidase (5), but the identity of the enzyme with kallikrein was not clear because of the lack of study on the biological activity of the preparation. Fiedler, et al. described that hog submaxillary kallikrein was separated into a number of active components with isoelectric points in the range pH 3.3–4.4 (6), but the specific activity of their preparation was less than a half of that of purified hog pancreatic kallikrein. We attempted the isolation of kallikrein from the cat submaxillary gland and obtained a highly purified preparation which was homogeneous in disc electrophoresis.