[Mechanisms of the effect of polyamines on the complex-forming ability of blood plasma ribonucleases].

The study was concerned with the pathways of protein complexing in tumor growth. The effects of polyamines on blood plasma proteins and, particularly, on ribonuclease were investigated as a possible modifier of protein--protein interactions. In application of an ultrafiltration procedure, in vitro addition of polyamines to blood plasma imitated certain changes in plasma proteins which take place in tumor growth: filtrate showed a rise in the low molecular weight protein fraction, ribonuclease included. Peak concentrations of protein in filtrate were obtained virtually as soon as polyamines were added to incubation medium. The dissociating effect of polyamines was determined on the basis of the polyamine/protein ratio. Protein complexing was shown to be subject to the effects of both polyamines and products of their enzymatic oxidation.