Phosphorus Content of Ovalbumin and of some Products of its Enzymatic Degradation

Abstract

As is well known^1,2, the phosphorus content of ovalbumin does not, in general, correspond to an integral number of phosphorus atoms per mole of this protein if its molecular weight is taken as 44,000. About two years ago, Linderstrφm-Lang suggested to me that this lack of stoichiometry might be correlated with the occurrence, in ovalbumin, of two electrophoretically distinguishable components, A₁ and A₂³, the relative abundance of which varies somewhat from one preparation to another but averages about 85 per cent A₁ and 15 per cent A₂. In the course of the electrophoretic studies carried out in this laboratory of the ovalbumin plakalbumin transformation recently discovered by Linderstrφm-Lang and Ottesen^4–6, a modification of ovalbumin was encountered which crystallized in plates but differed electrophoretically from plakalbumin⁷. The solution from which these plate crystals were obtained was found to be contaminated with Gram-positive, rod-shaped bacteria, probably B. subtilis. In subsequent experiments a subculture from a single colony of this bacterial contaminant was kept in blood broth as the stock culture and was used as a source of enzymes for modifying ovalbumin. Phosphorus analyses of the proteins at different stages of enzymatic degradation were made. A comparison of these results with the electrophoretic analyses has made possible a test of Linderstrφm-Lang's suggestion.