Rat liver glutamine synthetase. Preparation, properties, and mechanism of inhibition by carbamyl phosphate.

摘要: Abstract Glutamine synthetase, purified from rat liver, is homogeneous on acrylamide gel electrophoresis and ultracentrifugation (s20,w, 15.0 S). The enzyme, which consists of eight subunits (subunit molecular weight, 44,000), resembles ovine brain glutamine synthetase in its physical properties, amino acid composition, substrate specificity. Complete inhibition the liver enzyme by methionine sulfoximine associated with binding 4 moles inhibitor per mole enzyme. activated α-ketoglutarate (in presence Mg++ or Mn++) inhibited glycine, l-alanine, l-serine, carbamyl phosphate (with Mn++ only). Evidence presented that produced this compound to active site synthetase. Thus, can catalyze synthesis ATP ADP. When incubated ADP, phosphate, glutamate, formed. Enzyme inactivated treatment did not utilize phosphate. Liver also catalyzes ADP acetyl phosphate; reaction competitively glutamate. synthetases brain, Escherichia coli