title: Partial characterization of an abnormal lactate dehydrogenase isoenzyme, LDH-1ex, in serum from a patient with hepatocellular carcinoma.
abstract: Serum from a patient with hepatocellular carcinoma contained an abnormal isoenzyme of lactate dehydrogenase (LDH; EC 1.1.1.27), LDH-1ex, that on electrophoresis on 10-g/L agarose gel migrated anodally to the LDH-1 band. This isoenzyme was partly purified by ultrafiltration and preparative electrophoresis. Gel chromatography and sodium dodecyl sulfate/polyacrylamide gel electrophoresis studies of the resulting LDH-1ex preparation suggested that this isoenzyme is probably a tetramer made up of four single polypeptide chains (monomers), each having a molecular mass of about 32,000 Da. LDH-1ex was heat stable and reacted more readily with 2-hydroxybutyrate than did the slower migrating LDH-4 and LDH-5 isoenzymes. LDH-1ex showed no activity when lactate was omitted from the substrate solution or replaced by ethanol.
authors: Department of Biochemistry, School of Medicine, University of Patras, Greece.
authors: D L
authors: DL
authors: Kalpaxis
authors: E E
authors: EE
authors: Giannoulaki
mesh_terms: D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000097:blood / Q000201:enzymology*; D002850:Chromatography, Gel; D004587:Electrophoresis, Agar Gel; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D006884:Hydroxybutyrate Dehydrogenase / Q000097:blood; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000097:blood* / Q000302:isolation & purification; D008113:Liver Neoplasms / Q000097:blood / Q000201:enzymology*; D008970:Molecular Weight; D000509:alpha-Fetoproteins / Q000032:analysis
chemical_list: D007527:Isoenzymes; D000509:alpha-Fetoproteins; D007770:L-Lactate Dehydrogenase; D006884:Hydroxybutyrate Dehydrogenase