Crystalline Leghemoglobin. X. The Ferrihemochrome of Leghemoglobin.

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Abstract
The absorption spectrum of anhydro-fer-rileghemoglobin (ferriLhb) in anhydrous glycerol has been measured and found to be that of a ferrihemochrome. A faint absorption observed at 623 nm is assumed to indicate complex formation between the ferric iron of the ferrihemochrome and the alcohol groups of glycerol. The ferrihemochrome was rapidly converted to acidic ferriLhb on addition of water. Acidic ferriLhb could be transformed into ferrihemochrome by exposure to high concentrations of neutral salts like NaClO4 and MgCl2. On dilution, a re-transformation into ferriLhb occurred. The spectral curves representing different concentrations of salt intersect at 5 isosbestic points, 664, 592, 514, 483, and 412 nm, respectively. Rapidly prepared centrifugates of crushed soya bean nodules showed a ferrihemochrome type of spectrum, which on reduction was transformed into that of ferrohemochrome. Only a low percentage of ferriLhb could be demonstrated in the extract, the predominant form of Lhb being that of ferrihemochrome. Precipitation with ammonium sulfate caused a partial transformation of the ferrihemochrome to acidic ferriLhb. Ferri-(ferro-)hemochrome is concluded to be the native form of Lhb present in the root nodules.