Electrophoretic Characterization of Pregastric Esterase from the Calf

SU]V[IV[ AR¥This investigation was conducted primarily to determine whether pregastrie esterase from the calf is a single enzyme or a group of enzymes.Accordingly, sham-fed water and extracts of various alimentary and related tissues were subjected to eleetrophoresis in starch gel, which was stained histochemically to locate individual esterases.The results indicate that pregastric esterase is composed of at least six different enzymes.Resolution of these esterases was obtained in gel containing 8 g of starch per 100 ml of buffer, but not in that containing 15 g per 100 ml.Thus, the components of pregastric esterase are believed to be of high molecular weight.Moreover, these esterases precipitate at a slightly acid pH, thereby providing a means of separating pregastric esterase from nonsecretory esterases that are present also in tissue extracts.Pregastrie esterase is an enzyme found in the oral secretions of the young calf.The secretion of pregastric esterase and its importance in fat digestion have been considered previously (3, 7, 9, 11, 12), though it has not been ascertained whether this esterase is a single enzyme or a group of enzymes.Recent studies with starch gel electrophoresis (2, 4), however, indicate that many animal tissues contain more than one esterase.Thus, the primary objective of the present investigation was to study the electrophoretic identity of pregastric esterase, in order to establish its singular or multiple nature.The initial phase of this study was a survey of the electrophoretic distribution of esterases in extracts of various tissues believed to secrete pregastrie esterase.Other alimentary and related tissues were included also for comparative purposes.In the latter phase of this study, efforts were continued toward the identification of pregastric esterase and the isolation of this enzyme from nonsecretory esterases.The experimental procedures and the results and discussion for each area of investigation are presented separately.