Gastric digestive proteinases of the greater horseshoe bat, Rhinolophus ferrumequinum

Abstract

Pepsinogens are zymogens of pepsins, the gastric digestive proteinases found in vertebrates. Pepsinogens A and C are the main components occurring in adult mammals, and prochymosins and pepsinogen F are expressed specifically in neonatal mammals. It is known that the relative levels of pepsinogens A and C in the gastric mucosa differ among different species of mammals. Three major pepsinogens (A, C, and prochymosin-like zymogen (PLZ)) were purified from the greater horseshoe bat Rhinolophus ferrumequinum using DEAE-Sephacel chromatography and fast protein liquid chromatography. The relative levels of these three zymogens, based on their activity in the gastric mucosa, were calculated to be 36% for A, 48% for C, and 16% for PLZ. The expressional pattern of pepsinogens A and C were similar to those previously found in the house musk shrew Suncus murinus and amongst artiodactyls, but differed significantly from those found amongst. rodents, in rabbit Oryctolagus cuniculus, and amongst carnivores. The PLZ appears to be a novel type of pepsinogen specific to bats. The enzymatic properties of bat pepsinogens are also described.