Partial purification and properties of rat liver glutaminase.
The mitochondrial enzyme phosphate-dependent glutaminase was partially purified from rat liver. The enzyme had Mr 290 000 as judged by chromatography on Sephacryl S-300. After sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of the preparation, glutaminase was tentatively identified with a peptide of Mr 73 500. The concentration-dependence on glutamine was highly sigmoidal, with half-maximum velocity at 22 mM-glutamine. Half-maximum activity was obtained with 5 mM-phosphate. The enzyme required ammonia as an obligatory activator, in agreement with previous reports on intact and sonicated mitochondria. These findings further differentiate liver glutaminase from the phosphate-dependent glutaminase present in kidney and several other tissues.
D000643:Ammonium Chloride / Q000494:pharmacology; D000818:Animals; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D005972:Glutaminase / Q000302:isolation & purification / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D007700:Kinetics; D008930:Mitochondria, Liver / Q000201:enzymology*; D008970:Molecular Weight; D010710:Phosphates / Q000378:metabolism; D051381:Rats
D010710:Phosphates; D000643:Ammonium Chloride; D005973:Glutamine; D005972:Glutaminase