Figure 2 Absorption spectra of the purified avian complex II preparation. Complex II was diluted to 6.8  µM in buffer containing 20  mM K-MOPS pH 7.5, 100  mM NaCl, 0.5  mM EDTA, 0.1  g  l-1 dodecyl maltoside. A portion of this dilution was used to determine the heme content from pyridine hemechrome spectra as described. Another portion was used directly to take spectra before (red) and after (black) reduction by a trace of solid dithionite. The difference (reduced minus oxidized) is plotted in magenta. The absorption scale has been normalized to directly read the extinction coefficient for the portion of the spectra beyond 470  nm. The region before 470  nm is plotted on a 4× reduced scale.

© International Union of Crystallography 2005