TABLE 2.

Extracellular protease activity determined in the culture supernatant

Protease	Additives	Activitya (U/mg of protein) of strain:
		ISP794	BF16	BF17
Total protease		440	≤15	580
Serine protease		380	≤15	470
Metalloprotease		110	≤15	96
Thiol protease	DTT, EDTA	11,100	160	13,300
	DTT, EDTA, PMSF (1 mM)	10,700	100	12,900
	DTT, EDTA, PHMB (3 mM)	230	100	110
	DTT, EDTA, iodoacetamide (1 mM)	130	90	NDb

^aUnits of serine protease and metalloprotease were determined by subtraction of units obtained with PMSF (1 mM) and EDTA (1 mM), respectively, from the total units of proteolytic activity. Thiol protease activities were measured in the presence of DTT (1 mM) and EDTA (1 mM). 

^bND, not determined.