3.4.23.18	1.6	4	about half-maximal activity at pH 1.6 and 4, no activity below pH 1 and above 5	
3.4.23.18	2	6	about 5% activity at pH 2.0, 100% activity at pH 2.5, about 95% activity at pH 3.0, about 60% activity at pH 3.5, about 50% activity at pH 4.0, about 15% activity at pH 5.0, about 3% activity at pH 6.0	
3.4.23.18	2.2	3	-	
3.4.23.18	2.3	4.3	about half-maximal activity at pH 2.3 and 4.3, cytochrome c	
3.4.23.18	2.6	6	-	
3.4.23.18	3.5	6.5	about half-maximal activity at pH 3.5 and 6.5, urea-denatured hemoglobin	
3.4.23.18	8	12	the enzyme is active over a broad alkaline pH range of 8.0-12.0