Ostrich pepsins I and II: A kinetic and thermodynamic investigation

Comparison of pig and chicken pepsins for protein hydrolysis

“…Some studies have shown that pepsins of various species, in particular mammals and birds, do not have the same enzymatic properties [3,22,28]. Concerning the controversy about the optimum pH of pepsins from avian species, our results confirmed those of studies that showed a higher optimum pH of pepsins in birds than in pigs [3,33,35].…”

“…These optimum pHs are defined for haemoglobin. The optimum pH of an enzyme depends, however, on its substrates, as do those of gastric proteases [28]. In our study, we observed that while the optimum pH was 2 and 2.5-3 for haemoglobin hydrolysis with porcine and chicken pepsins, respectively, they were lower for the two plant proteins tested.…”

“…Contamination of chicken pepsin with cellular enzymes was probably not at the origin of the larger pH activity range. A larger pH range of avian pepsin activity compared to pig pepsin was also observed with purified chicken [3] or ostrich [28] pepsins. Avian pepsins seem less sensitive to non-optimal pH values, especially the highest pH values, than the pig pepsin.…”

“…Les [32], than in pigs, about 5 h 30 min for soluble compounds and 14 h 30 min for insoluble compounds [7]. Moreover, the characterization of avian enzymes reveals differences with respect to activities and inhibitor sensitivities as compared to mammalian enzymes [3,[17][18][19]28].…”

“…It is also used with plant proteins [11,16]. But, porcine pepsin (composed mainly of pepsin A) is used whatever the species despite some studies have shown that pepsins from different species show different enzymatic properties [3,22,28]. [35] was not chosen because of contamination of the preparation with large amounts of mucin-like materials and a loss of activity observed by Bohak [3].…”