. Author manuscript; available in PMC: 2009 Oct 1.

Published in final edited form as: J Am Soc Mass Spectrom. 2006 Oct 4;18(2):167–178. doi: 10.1016/j.jasms.2006.08.010

Table 1.

Accurate mass measurements of APS reductase and its associated complexes

Enzyme forms	M_exp (Da)^a	M_theor (Da)^b	ΔM (ppm)	disulfide number	cluster oxidation state
Apo	28352.376±0.073	28352.235	+5.0	2	N/A
Apo+2Fe-2S	28530.192±0.107	28530.078	+3.9	0	+2
Apo+4Fe-4S (E)	28705.995±0.058	28705.879	+4.0	0	+2
E-SO₃H	28785.971±0.064	28785.836	+4.7	0	+2
E·AMP	29053.051±0.075	29052.902	+5.1	0	+2
E-SO₃H·AMP	29133.029±0.077	29132.898	+4.5	0	+2

The average experimental value of the most abundant isotopic mass over the charge state distribution. The most abundant isotopic mass was assigned after the average mass was first determined as described in the experimental section. Four measurements were made for each mass assignment. All spectra were internally calibrated against carbonic anhydrase.

The most abundant isotopic mass determined from theoretical simulation.