ABSTRACT
The crude leghaemoglobin suspension from root nodules of yellow lupine (Lupinus luteus L.) was separated into five fractions: I, IIa and IIb, IIIa and IIIb using the chromatography on DEAE-cellulose (numbered following the elution order). The visible absorption spectra show that fractions I, IIa and IIIa are met-leghaemoglobins while IIb and IIIb are oxy-forms. IIb and IIIb were converted to IIa and IIIa respectively when oxidized with potassium ferricyanide. The determination of two first N-terminal amino acids confirms the identity of pairs IIa-IIb and IIIa-IIIb. Three components of leghaemoglobin were obtained having the following N-terminal amino acids: Gly-Val- (the first), Gly-Ala- (the second), Ala-Val- (the third). The molecular weights obtained by Archibald's method are 17 900, 17 600, 18 800 respectively. The second leghaemoglobin species which contains more than 50% of the starting protein mixture was used to grow crystals for X-ray study of the tertiary structure of this protein.
