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Biomedical subjects

K Harada

Publications and source records attributed to K Harada.

At least 1,243 records · Page 69Linked to original sources
PubMed1978

Hybrid isozymes of rat pyruvate kinase. Their subunit structure and developmental changes in the liver.

Thin-layer polyacrylamide gel electrophoresis of various rat tissues revealed three major isozymes (types L, M1 and M2) and various intermediate forms of pyruvate kinase (ATP: pyruvate 2-O-phosphotransferase, EC 2.7.1.40). In vitro dissociation and reassociation of purified enzymes showed that the three major isozymes had homotetrameric structures. L.M2 hybrids and M1.M2 hybrids closely resembled some naturally occurring intermediates; the subunit structure of intermediates isolated from the small intestine (form 3 or form 4) were estimated to be (L)2(M2)2 and (L)(M2)3, respectively. Pyruvate kinase activity after electrophoresis could be estimated quantitatively from densitometric measurements of the electrophoretic pattern. Type L activity in fetal liver was separated from type R activity derived from intrahepatic erythropoietic cells. It changes in three distinct steps during development: it increased during the late fetal period, remained steady during the neonatal period and increased again after weaning. Some of the intermediates found in extracts of early fetal iver were shown to cross-react with both anti-L and anti-M1 serum, suggesting that they might be L.M2 or R.M2 hybrids. These hybrid enzymes were shown to appear only during early fetal and neonatal periods.

Animals↗
PubMed1978

Purification of four pyruvate kinase isozymes of rats by affinity elution chromatography.

1. Purification of four isozymes of pyruvate kinase (ATP:pyruvate 2-O-phosphotransferase, EC 2.7.1.40) L, M1, M2 and R was much improved to give good yields by affinity elution chromatography. The enzyme was eluted from a phosphocellulose column with 0.5 mM phosphoenolpyruvate. Types L, M2 and R were stabilized with fructose 1,6-diphosphate throughout the purification procedures. 2. The isozymes were crystallized under various conditions: types L and R were readily crystallized from medium of low ionic strength, types L, M1, and M2 were crystallized from ammonium sulfate solution in different forms in the presence and absence of phosphoenolpyruvate. Type M1 was also crystallized in different forms in the presence and absence of fructose 1,6-diphosphate. 3. Amino acid analyses showed that the compositions of types L and R, and of types M1 and M2, respectively, were very similar.

Amino Acids↗
PubMed1978

Formation of amino acids from aliphatic nitriles and aliphatic amines by contact glow discharge electrolysis.

Contact glow discharge electrolyses (CGDE) were carried out relative to the prebiotic formation of amino acids by amination of aliphatic nitrile in aqueous ammoniacal solution, and by cyanization of aliphatic amine by sodium cyanide. The CGDE of propionitrile by amination followed by hydrolysis resulted in the formation of glycine, alanine and beta-alanine. The reaction of ethylamine by cyanization, gave glycine, alanine, beta-alanine, aspartic acid, and serine. In these reactions, a relatively high ratio of glycine was observed. This could be explained by the cleavage of the alpha,beta-carbon bond, which was broken easily, due to the strong electron-attracting property of the nitrile group of propionitrile and the resulting alpha-aminopropionitrile.

Amines↗