High level expression and biochemical characterization of an alkaline serine protease from Geobacillus stearothermophilus to prepare antihypertensive whey protein hydrolysate

Table 1 Purification summary of GsProS8

Purification step	Total activity (U)^a	Total protein (mg)^b	Specific activity (U/mg)	Purification factor	Yield (%)
Crude protease	116,250 ± 2089.3	68.5 ± 4.1	1697.1 ± 30.2	1.0	100.0
Ammonium sulfate precipitation	86,460 ± 1965.2	41.6 ± 1.9	2078.4 ± 47.5	1.2	74.4
SPFF	50,806 ± 190.5	22.4 ± 5.4	2268.1 ± 9.1	1.3	43.7
QSFF	27,409 ± 373.9	7.7 ± 1.2	3559.7 ± 48.4	2.1	23.6

^aEnzymatic reaction was carried out using casein as a substrate at 50 °C in 0.05 mol/L MOPS buffer (pH 8.5)
^bTotal protein was measured using BSA as standard by the Lowry method

ISSN: 1472-6750