DNA, oligosaccharides, and mononucleotides stimulate oligomerization of human lactoferrin.

Using small-angle X-ray scattering (SAXS), light scattering (LS), and soft laser ablation we have shown that lactoferrin (LF) in solution at neutral pH is oligomerized in the absence of salt or at physiological salt concentrations. The level of oligomerization depends on the concentration of LF, KCl or NaCl, and on the duration of the protein storage in solution. At the concentrations comparable with those in human milk (1-6 mg/ml), the average radius of gyration (R(g)) values of LF can attain 400-480 A, while fresh solution of previously lyophylized LF demonstrate a lower average R(g) (50-100 A), and R(g) value characterizing the LF monomer formed at 1 M NaCl is 26.

[Optical rotary dispersion of some heptaene antibiotics].

Experimental differences in the curves of the optic rotation dispersion (ORD) of cystrans-heptaenic antibiotics were found. The ORD curves of amphotericin B, mycoheptin, levorin components and isolevorin A2, components of criptomycin and candidin were registered. The curves of the ORD which were smooth had been prepared in dimethylsulphoxide in the spectral range at 450 to 600 nm.