ZONE ELECTROPHORESIS OF PROTEIN-BOUND PHOSPHORUS OF FOWL'S SERUM

Abstract

The movement of protein-bound phosphorus on zone electropherograms of fowl sera has been studied (a) by use of reactions for ester-linked protein phosphorus (ELPP) and (b) by use of sera in which the phosphorus had been labelled with P32. Serum from estrogenized pullets yielded two major lipoprotein zones, P-1 and P-2, on electrophoresis in veronal buffer pH 8.6. Most of the ELPP or protein-bound P32was associated with these two zones, although minor amounts of protein-bound P32were detected in other zones except the albumin zone. Somewhat similar results were obtained with borate buffer pH 9.0.Use of veronal–citrate buffer pH 8.6, or pretreatment of the serum with ethylenediaminetetraacetate, or removal of the serum calcium by oxalate precipitation abolished the resolution of two lipoprotein zones, which were replaced by a single lipoprotein zone. At the same time most of the ELPP or protein-bound P32moved to a zone just ahead of the albumin zone.It is suggested that chelation or removal of the serum calcium led to dissociation of phosvitin from the lipoproteins of the serum and the independent migration of this phosvitin to a zone slightly ahead of the albumin zone.The pre-albumin zones of sera from chick embryos did not give any staining reaction for ELPP. This observation supports the conclusion that the prealbumin zones of sera from embryos and of sera of estrogenized pullets or laying hens are due to different proteins, and that phosvitin is either absent from embryo serum, or present in amounts below the limit of sensitivity of the reaction used for its detection.