Purification and properties of a C-type isozyme of lactate dehydrogenase from the liver of the Atlantic cod (Gadus morhua).
A C-type lactate dehydrogenase isozyme has been purified to homogeneity from the liver of the Atlantic cod. The enzyme consists of four identical subunits each with a mol. wt of 35,000. Optimum concentrations, Kms, and relative activities were determined for various substrates along with the optimum pH for the reaction with pyruvate and lactate. Glyoxalate, alpha-ketobutyrate, alpha-ketovalerate, and alpha-ketoglutarate were significantly reduced but branched chain alpha-ketoacids were not utilised as substrates. Substrate inhibition was observed for both lactate and pyruvate as is generally found for B-type lactate dehydrogenase isozymes but the lactate optimum concentration and Km more closely resemble the A-type lactate dehydrogenases.
D000818:Animals; D005399:Fishes; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000302:isolation & purification* / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D008970:Molecular Weight; D013045:Species Specificity
D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase