Hydrolysis of whey proteins by proteases extracted from Cynara cardunculus and immobilized onto highly activated supports

摘要

Blends of cardosins A and B, enzymes present in aqueous extracts of the flowers of the thistle (Gynara cardunculus L.), have for Ion been used as rennets by the cheesemaking industry in the Iberian Peninsula. These dimeric proteases are present in the stigm~e and stylel of said flowers, and are thought to play a role in sexual reproduction of the plant. In the present research effort, production of cardosi derivatives (starting from a crude extract), encompassing full stabilization of their dimeric structure, has been attempted via covaleni multi-subunit immobilization onto highly activated agarose-glutaraldehyde supports. Boiling such enzyme derivatives in the presence o sodium dodecyl sulfate and f3-mercaptoethanol did not lead to leaching of enzyme, thus proving the effectiveness of the attachmen procedure. Furthermore, derivatives prepared under optimal conditions presented ca. half the specific activity of the enzyme in soluble form and were successfully employed at lab-scale trials to peiform (selective) hydrolysis of a-lactalbumin, one of the major proteins in hovint whey.