A proteolytic enzyme obtained from the juice of the fruit of Bromelia pinguin Plum. ex L., Bromeliaceae (pineapple family): Asenjo, Science 95, 48 (1942); Bloch, Messing, US 2977287 (1961 to Ethicon). Immunochemical studies: E. Toro-Goyco, I. Rodriguez-Costas, Arch. Biochem. Biophys. 175, 359 (1976). Structure studies: E. Toro-Goyco et al., Biochim. Biophys. Acta 622, 151 (1980).