Can Recombinant Tree Shrew (Tupaia belangeri chinensis) Chymosin Coagulate Cow (Bos taurus) Milk?

Abstract Genetically engineered chymosin from the tree shrew ( Tupaia belangeri chinensis ) has been obtained and partially characterized for first time. The target enzyme was produced in Escherichia coli , strain BL21(DE3). It shown that recombinant coagulates cow milk Bos taurus ). total specific milk-clotting activity of 0.7–5.3 IMCU/mL 8.8–16.6 IMCU/mg. nonspecific proteolytic relation to bovine casein 30 117% higher than single-humped camel respectively. found comparison with most known genetically chymosins, showed exceptionally low thermal stability. After heating at 45°C, coagulation ability decreased by more 40%, 50°C lost 90% initial activity. Michaelis constant K m ), turnover number k cat catalytic efficiency / were 6.3 ± 0.1 µM, 11 927 3169 s –1 1968 620 µM Comparative analysis primary structure chymosin-sensitive site kappa-casein supposed similar sequence differed 75%. coagulate cow’s milk, along a stability high respect substrate, imitating kappa-casein, suggests this is potential interest cheese making.