title: An enzymatic method for radiolabeling vertebrate vitellogenin.
abstract: Phosphoprotein kinases from Xenopus and chicken liver have been purified and these enzymes have been used to label Xenopus vitellogenin, a phosphoprotein, to high specific activity with [gamma-32P]ATP. The enzymes were isolated by (NH4)2SO4 fractionation followed by chromatography on DE-52 cellulose and phosphocellulose. This procedure resulted in greater than 20,000-fold enrichment for the enzymes. Both enzyme preparations were used to selectively label vitellogenin in the serum of estrogen-treated animals. Thus, isolation of the vitellogenin prior to radiolabeling was not necessary. The [32P]vitellogenin labeled in situ was incorporated by oocytes at a rate similar to [32P]vitellogenin labeled in vivo, was translocated to the yolk platelets, and was correctly processed into the yolk proteins.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002645:Chickens; D004527:Egg Proteins / Q000378:metabolism; D005260:Female; D007553:Isotope Labeling / Q000379:methods*; D008074:Lipoproteins / Q000378:metabolism; D008099:Liver / Q000201:enzymology; D008297:Male; D009865:Oocytes / Q000378:metabolism; D010761:Phosphorus Radioisotopes; D011494:Protein Kinases / Q000378:metabolism*; D013379:Substrate Specificity; D014819:Vitellogenins / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D004527:Egg Proteins; D008074:Lipoproteins; D010761:Phosphorus Radioisotopes; D014819:Vitellogenins; D000255:Adenosine Triphosphate; D011494:Protein Kinases