[Constitutive proteins of the oocytes and early embryos of rats]

5 protein fractions were identified and their relative mobility was determined in the rat oocytes and cleaving embryos by means of vertical capillary microdisc-electrophoresis in 7.5% polyacrilamide gel (PAA-gel). The same fractions were identified in the cleaving embryos devoid of zona pellucida. A conclusion was drawn that these proteins were present in the oocyte cytoplasm and kept in the cleaving embryos until the stage of implantation. 4 groups of proteins with different anodic mobility were identified in the isolated zona pellucida by means of microdisc-electrophoresis in 7.5% PAA-gel added with 1% sodium dodecylsulfate (SDS). The molecular weight of low molecular weight proteins of oocytes and preimplantation embryos was determined by means of disc-electrophoresis in 14% PAA-gel with 1% SDS. The zona pellucida of one embryo contained, according to the data of capillary spectrophotometry, 5 ng of protein.