The molecular weight of bovine lactoferrin

Abstract

The molecular weight of bovine lactoferrin in a neutral solvent (e.g. 0.2 M NaCl, pH 7.8, 20 °C) has been determined using high-speed sedimentation equilibrium at various concentrations and speeds. Under these conditions the protein behaved as a single thermodynamic component with a weight-average molecular weight [M w] c=0 = 93 000 ± 2000 and a second virial coefficient B = 4.3 · 10 −5 mol · ml −1 · g −2. This value of the molecular weight is in good agreement with values previously reported by Groves (J. Am. Chem. Soc. 82, 3345–3350, 1960) and Szuchet and Johnson (Eur. Polym. J. 2, 115–128, 1966); it is, however, in disagreement with the more recent value given by Castellino et al. (J. Biol. Chem. 245, 4269–4275, 1970). The possible reasons for this discrepancy are discussed.