Etude des protéases de quelques plantes endémiques.

Abstract

A study was carried out on two local spinous plants of the genus Scolymus in order to extract enzymes having a technological interest. For this, acid proteases were purified from flowers Scolymus maculatus and Scolymus hispanicus in three steps, fractional precipitation with AS, molecular sifting and ion exchange chromatography. The yields activity recovered are 30.56% and 20.97%, with purification degrees of 60.51 and 57.60 for S. maculatus and S. hispanicus respectively. The separation of acid proteases by SDS-PAGE gave a molecular weight of 45 kDa for both enzymes. The study of physicochemical properties allows obtaining an optimum pH of 5, an optimum temperature of 55°C and a stability of 1 hour and a half. These enzymes are inhibited by pepstatin A indicating that it is aspartylprotease; they are activated by Ca+2. The kinetic parameters of these proteases are Vm 1391 U and 1367 U, KM 4.76 g/L and 5.71 g/L for S. maculatus and S. hispanicus respectively. These enzymes cause a very rapid coagulation of fresh cow's milk in very short times: 7 min for the enzyme of S. maculatus and 10 min to that of S. hispanicus. The coagulant activity of these proteases is optimum at 60 ° C and pH 5, at a concentration of 50 mM in calcium. These coagulases have the ability to hydrolyze ,  and casein. These results indicate that these enzymes can be used as substitutes for rennet. Other properties tested with alkaline proteases extracted from the same plants showed different technological potential. Thus, these enzymes can act as anticoagulants, detergents and keratinase. Which allows the use in industrial applications.