RESUMEN
The leghemoglobin from nodules of Crotalaria juncea infected with Rhizobium spp. was purified to homogeneity. The protein was purified after precipitation with 40-80% (NH4)2SO4, and chromatography by anionic exchange and gel filtration. The leghemoglobin has a single component and showed an apparent M(r) of ca. 17,300 and 23,700 determined by SDS-PAGE and gel filtration, respectively. The amino acid composition showed that asparagine/aspartic acid, glutamine/glutamic acid, alanine, lysine, serine and leucine were the main amino acids. Iron was detected only in the band corresponding to the purified protein. The N-terminal amino acid sequence for the first 19 residues showed high similarities with several other leghemoglobins from other plants.