CASEINOLYTIC AND MILK-CLOTTING ACTIVITY OF Solanum tuberosum ASPARTIC PROTEASES (StAPs)

FREY, MARIA EUGENIA; GUEVARA, MARIA GABRIELA; PEPE, ALFONSO; DALEO, GUSTAVO RAÚL; TITO, FLORENCIA ROCIO; D'IPPÓLITO, SEBASTIÁN

Córdoba

Congreso; 52th Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2016

Increased interest in find suitable calf rennet substitutes for cheese making has led to the screening of new proteases to be used as natural milk coagulants. Several plant proteases obtained from fruits, roots, latex and flowers has shown milk- clotting activity. The aim of this work was to detect and characterize the milk-clotting activity of two Solanum tuberosum aspartic proteases, StAP1 and StAP3. They were previously isolated from potato tubers (StAP1) and leaves (StAP3). Both enzymes hydrolyzed casein over a broad temperature range (40-60°C). The caseinolytic activity of StAP3 was three times higher than the one from StAP1 at all temperatures tested. The optimum pH of both enzymes to hydrolyze casein was 8. We also evaluated the milk-clotting activity of StAP1 and StAP3, being 1.69 and 1.96 milk clotting units, to StAP1 and 3, respectively. These values are similar to the activities found in commercial rennet. These results suggest a new potential use in bioprocesses to StAPs, particularly as a milk coagulant for cheese making.