A quantitative study of complex formation in heated protein mixtures

Abstract

When heated alone both tobacco mosaic virus (tmv) and tomato bushy stunt virus (tbsv) coagulate whereas human serum albumin does not. When the albumin/ virus ratio in a complex is 1.8 or higher the complex forms a stable soln. All the virus and only part of the albumin participate in the formation of such a complex. Heat-denatured tmv combined with albumin contains no nucleic acid and has no serological activity, whereas the complex of tbsv retains both. When the albumin/tbsv ratio in the complex is over 3, the complex is not precipitable by virus antibodies although it combines with them. At a constant virus concn. the albumin/ virus ratios in the complex increase with increasing albumin concn.; the ratios decrease with increasing virus conc. when the albumin concn. is constant; the ratios increase with increasing total protein concn. when the proportions are constant. Under similar conditions about 2.4 times as much albumin combines into a complex with heat-denatured tmv as with tbsv. Heat-denatured albumin molecules aggregate more rapidly with particles of heat-denatured viruses than with one another.