Studies on glutamine synthetase from Escherichia coli. Formation of pyrrolidone carboxylate and inhibition by methionine sulfoximine.

Studies on Glutamine Synthetase from Escherichia coli FORMATION OF PYRROLIDONE CARBOXYLATE AND INHIBITION BY METHIONINE

Both the adenylylated and unadenylylated forms of Escherichia coli glutamine synthetase catalyze the formation of pyrrolidone carboxylate from glutamate in the presence of ATP and divalent metal ions (Mg++ or Mn++) and in the absence of ammonia. The unadenylylated enzyme catalyzes this reaction more rapidly with Mg++ than with Mn++, while the adenylylated enzyme catalyzes it more rapidly with M...

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

Glutamine synthetase, purified from rat liver, is homogeneous on acrylamide gel electrophoresis and on ultracentrifugation (~20,~) 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, and substrate specificity. Complete inhibition of the liver enzyme by methionine ...

Conformational differences between unadenylylated and adenylylated glutamine synthetase from Escherichia coli on binding L-methionine sulfoximine.

Differential Inhibition of Glutamine and y-Glutamylcysteine Synthetases by a-Alkyl Analogs of Methionine Sulfoximine That Induce Convulsions*

The a-methyl and a-ethyl analogs of methionine sulfoximine, like methionine sulfoximine, induce convulsions in mice and inhibit glutamine synthetase irreversibly; cu-ethylmethionine sulfoximine is approximately 50% as inhibitory as methionine sulfoximine and a-methylmethionine sulfoximine. However, whereas cy-methylmethionine sulfoximine and methionine sulfoximine inhibit y-glutamylcysteine syn...

Inhibition of glutamine synthetase by methionine sulfoximine. Studies on methionine sulfoximine phosphate.

The irreversible inhibition of glutamine synthetase by methionine sulfoximine is associated with the tight binding to the enzyme of adenosine diphosphate and methionine sulfoximine phosphate; the latter compound can be cleaved nonenzymatically and also by phosphatases to equimolar amounts of methionine sulfoximine and inorganic phosphate. Methionine sulfoximine phosphate is oxidized by L-amino ...