A COMPARISON OF PHOSVITINS PREPARED FROM HEN'S SERUM AND FROM HEN'S EGG YOLK

Abstract

A phosvitin has been prepared from the serum of estrogenized laying hens and partially characterized on the basis of its contents of N (12.3%), P (10.1%), serine (31,0%), and tryptophan (0.56%). Examination of this serum phosvitin and a yolk phosvitin preparation for N-terminal groups yielded identical chromatographic patterns. Alanine was the major N-terminal amino acid with minor amounts of N-terminal lysine. The sedimentation constant s02.0w =3.7, weight-average molecular weight 4.2 x 104 (Archibald method), and number-average molecular weight 4.0 x 104 (calculated from the tryptophan content) of the serum phosvitin were similar to those of the phosvitin prepared from egg yolk by the same preparative technique. The two preparations behaved similarly when subjected to zone electrophoresis on paper. Zone electrophoretic evidence is submitted for the presence of phosvitin in the supernatant from dilution precipitation of crude lipophosphoprotein from laying hen''s serum as well as in the precipitate itself.