Structural proteins of plasmolemma of the jejunum absorbing enterocytes of cattle fetus in early fetal period

The data on the concentration of structural proteins of plasmolemma of the absorption enterocytes of the cattle fetus in the early fetal period are presented. Changes in the protein composition of the apical and basolateral membranes of enterocytes are manifested, characterized not only by changes in their ratio within different cell domains, but also by the dynamic redistribution of the number of different fractions of polypeptides between the poles of these cells. Analysis of the results of electrophoresis of apical membranes of the cattle fetus enterocytes in the early fetal period indicates a decrease in the content of low molecular weight protein fractions and an increase in high molecular weight. In the apical membranes of enterocytes of two-month-old cattle fetus, 25 protein fractions with a molecular weight of 9.6 to 205 kDa were detected. In the basolateral membranes revealed 23 protein fractions with a molecular weight of 9.6 to 120 kDa. High molecular weight fractions of polypeptides with molecular weights of 250 kDa and 300 kDa appear from the age of three months of embryos of calves. In the basolateral membranes of enterocytes, there is a slight decrease in the content of low molecular weight protein fractions, and from the four months of age of cattle fetus, high molecular weight fractions of polypeptides with molecular weights of 22.5 kDa and 155 kDa appear, which are absent in basolateral membranes of enterocytes. Two-month-old fetus lack proteins with a molecular weight of 19 kDa, 24 kDa, and 66 kDa in the apical part, whereas proteins with a mass of 22.5 kDa, 155 kDa, 170–185 kDa, and 205 kDa are absent on the basolateral membrane. In the apical membrane of enterocytes significantly more proteins with a low molecular weight of 9.6-14.2 kDa (1.56 times; P ≤ 0.001), whereas in the basolateral membrane a significantly higher concentration of proteins with a molecular weight of 15.5 kDa (2.06 times; P ≤ 0.001) and 17 kDa (3.62 times; P ≤ 0.001).