Characterization of hepatic L-threonine dehydrogenase of chicken.
The L-threonine dehydrogenase (TDH) was purified approximately 1300-fold to a specific activity of approximately 18000 unit mg(-1) from chicken (Gallus domesticus) liver mitochondria. Purification was obtained by sequential chromatography on DEAE Cellulose, Phenyl Sepharose High Performance hydrophobic interaction, Affi-Gel Blue affinity and Matrex Gel Red A columns. The molecular weight of the subunit was estimated to be 36 kDa by sodium dodecyl-polyacrylamide gel electrophoresis. An apparent molecular mass of native protein between 62 and 74 kDa was obtained by gel filtration chromatography, suggesting a dimeric structure of TDH. The isoelectric point of TDH was determined by isoelectric focusing to be 5.3. Partial amino-terminal sequence analyses, carried out on two purified preparations of TDH, revealed a high degree of homology to the reported sequence of porcine TDH. The Michaelis constants for L-threonine and NAD for partially purified chicken hepatic TDH are 5.38 and 0.19 mM, respectively.
Yuan
J H
JH
Department of Animal Science, Cornell University, Ithaca, NY 14853, USA.
Austic
R E
RE
D000429:Alcohol Oxidoreductases / Q000737:chemistry* / Q000302:isolation & purification*; D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D002845:Chromatography; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D008930:Mitochondria, Liver / Q000201:enzymology; D008969:Molecular Sequence Data; D013053:Spectrophotometry
D000429:Alcohol Oxidoreductases; C023159:L-threonine 3-dehydrogenase