title: Postnatal changes in canine erythrocyte pyruvate kinase isozymes.
abstract: The isozyme pattern of pyruvate kinase in canine erythrocytes changes following birth. These changes have been followed by electrophoretic, immunologic, and kinetic measurements of the isozymes. At birth, a mixture of isozymes is present consisting of the M2 isozyme and hybrid molecules containing M2 and R subunits. With increasing animal age, the content of M2 subunits decreases and the content of R subunits increases. At 6 months of age, the isozyme pattern is indistinguishable from that of adult erythrocytes which contain only the R tetramer. We conclude that there is a switch in erythrocyte pyruvate kinase gene expression during the first 6 months of postnatural life. The existence of hybrid molecules during the switch indicates that both M2 and R genes are expressed within each erythroid precursor cell. The developmental changes in erythrocyte pyruvate kinase are consistent with the role of this enzyme in the regulation of the oxygen-transport function of canine hemoglobin by 2,3-diphosphoglycerate in the postnatal period.
mesh_terms: D019794:2,3-Diphosphoglycerate; D000375:Aging; D000818:Animals; D004163:Diphosphoglyceric Acids / Q000097:blood; D004285:Dogs; D004912:Erythrocytes / Q000201:enzymology*; D005260:Female; D005312:Fetal Blood / Q000201:enzymology; D005786:Gene Expression Regulation; D006454:Hemoglobins / Q000378:metabolism; D007527:Isoenzymes / Q000097:blood* / Q000235:genetics; D010100:Oxygen / Q000097:blood; D011247:Pregnancy; D011770:Pyruvate Kinase / Q000097:blood* / Q000235:genetics
chemical_list: D004163:Diphosphoglyceric Acids; D006454:Hemoglobins; D007527:Isoenzymes; D019794:2,3-Diphosphoglycerate; D011770:Pyruvate Kinase; D010100:Oxygen