Glutamine synthetase from pig brain: binding of adenosine triphosphate.
Glutamine synthetase was purified to homogeneity from fresh brain homogenates by a procedure that makes use of the affinity of this ATP requiring ligase to Cibacron 3G-A Blue-Sephadex G-75. It is shown that the interaction of pig brain enzyme with the dye does not concern the active centre but a non-catalytic although specific ATP binding site. Both sides contain a cysteine residue which may react with N-ethylmaleimide. The unprotected succinimidated enzyme is inactive, and aggregates. ATP alone protects only against aggregation, not against inactivation; the ATP/Mg2 complex also hinders inactivation. A tryptic heptadecapeptide isolated from the derivatized enzyme representing the carboxy terminal seems to belong to the active centre; its amino acid sequence was partially determined.
D000255:Adenosine Triphosphate; D000818:Animals; D001921:Brain / Q000201:enzymology*; D005033:Ethylmaleimide / Q000494:pharmacology; D005974:Glutamate-Ammonia Ligase / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D010446:Peptide Fragments / Q000032:analysis; D011485:Protein Binding; D013552:Swine; D014357:Trypsin
D046911:Macromolecular Substances; D010446:Peptide Fragments; D000255:Adenosine Triphosphate; D014357:Trypsin; D005974:Glutamate-Ammonia Ligase; D005033:Ethylmaleimide