Janet M. Cardenas

TL;DR: Bovine muscle pyruvate kinase purified from bovine skeletal muscle by a procedure that includes only heat, ammonium sulfate fractionation, and chromatography on carboxymethyl Sephadex was found to be homogeneous, as determined by disc gel electrophoresis at pH 9.5 and the molecular weight in guanidine hydrochloride indicates the presence of four polypeptide chains in the native enzyme.

TL;DR: The isolated and purified the equivalent isozyme from bovine liver appears to have the same subunit structure and number of binding sites as the skeletal muscle isozyme, implying that, in spite of significant differences in physical and chemical properties, the liver and skeletal muscle isozymes are very similar.

TL;DR: Comparisons among the three mammalian and two avian isozymes of pyruvate kinase are consistent with a common evolutionary origin, perhaps from an ancestral form of the type K isozyme, which is the only pyruvent kinase identified in mammalian and avian embryos.

TL;DR: The distribution of pyruvate kinase isozymes was examined in cells and tissues from the central and peripheral nervous system of the rat, finding that adult pattern is achieved by a gradual shift from a hybrid set dominated by K4 in fetal life, to the pattern at birth at which time the two most prominent bands were M4 and K2M2, and finally to the adult pattern by about 28 days after birth.

TL;DR: Electrophoresis of various bovine tissue extracts revealed numerous intermediate bands that behave electrophoretically as hybrid isozymes, establishing the presence of the type M isozyme in a great many tissues other than striated muscle and brain, where it is most abundant.