Aminopeptidase B, a glucagon-processing enzyme: site directed mutagenesis of the Zn2+-binding motif and molecular modelling

Table 2 Effect of inhibitors on His-rAp-B activity.

		Percentage of inhibition *(L-Arg-β-NA Substrate)*
Inhibitors	Final concentration	Testis Enzyme*	E. coli Enzyme
O-phenanthroline	500 μM	76	80
	250 μM	55	67
	100 μM	27	6
	50 μM	-	0
EDTA	10 mM	95	71
	5 mM	84	65
	1 mM	34	53
NEM	1 mM	45	71
PMSF	500 μM	0	5
Bestatin	100 μM	-	100
	50 μM	100	98
	1 μM	68	94
Arphamenine A	1 μM	100	100
	500 nM	-	97
	200 nM	-	92
	100 nM	-	87
Arphamenine B	1 μM	100	100
	500 nM	-	100
	200 nM	-	99
	100 nM	-	95

The percentage of inhibition was calculated by taking as reference the amount of substrate conversion by His-rAp-B in absence of inhibitor (see Materials and Methods section). Values are the average of three independent series of tests in which each point was performed in triplicate. (* from [4])

ISSN: 1471-2091