Caseinolytic and milkclotting activity of solanum tuberosum aspartic proteases (StAPs).

TITO, F; PEPE, A.; FREY, MARÍA EUGENIA; D´IPPÓLITO SEBASTIÁN; DALEO GR; MARÍA G. GUEVARA.

Mendoza

Congreso; 52 Reunión anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2016

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

The need to find suitable calf rennet substitutes for cheese making has led to an increased interest in screening for new proteases to be used as natural coagulants. As an alternative, several proteases obtained from vegetal sources such as fruits, roots, latex and flowers have been recommended for use as milk-clotting agents. The aim of this work was to detect and characterize the milk- clotting activity of Solanum tuberosum aspartic proteases (APs), named as StAP1 and StAP3. These proteases were previously isolated form tubers (StAP1) and leaves (StAP3). Results obtained demonstrate that both enzymes were able to hydrolyze casein over a broad temperature range (40-60°C). StAP3 was 3 folds more active than StAP1, to hydrolyze casein at all temperatures assayed. Optimum pH to StAPs casein hydrolytic activity was 8. Additionally, we determinate that protease activity of StAPs were adequate to clot milk (1.69 and 1.96 milk clotting units mL-1, to StAP1 and 3, respectively) in clotting times similar to commercial rennet. These results suggest a new potential use in bioprocesses to StAPs, particularly as a milk coagulant for cheese-making.