Hydrocortisone has been found to induce glutamine synthetase activity in chick-embryo retinas in culture. Evidence is presented to show that the hydrocortisone is definitely required for transcription; its requirement for translation has not been ruled out. The possible identity of hydrocortisone with an active component of calf-serum diffusate reported earlier is discussed. The data also indic...

Glutamine Synthetase, Glutam ate Affinity, Isoenzymes, Positive Cooperativity, Thiol Compounds The chloroplastic glutamine synthetase taken from mustard leaves shows a positive cooperative glutamate binding. The S0.5-value depends on the DTE concentration in the homogenization buffer. Normal glutamate satura­ tion kinetics have been found with the root enzyme and the enzyme of etiolated cotyled...

The glutamine synthetases from several Pseudomonas species were purified to homogeneity, and their properties were compared with those reported for the enzymes from Escherichia coli and other gram-negative bacteria. The glutamine synthetase from Pseudomonas fluorescens was unique because it was nearly precipitated quantitatively as a homogeneous protein during dialysis of partially purified pre...

The formation of y-glutamylhydroxamate by homogenates under optimum assay condition showed an inconstancy in the ratios of the enzyme activities utilizing L-glutamate and ATP (y-glutamylhydroxamate synthetase) and L-glutamine and ADP (L-glutaminehydroxylamine glutamyltransferase) in a number of normal and neoplastic rat tissues. Although y-glutamylhydroxamate synthetase activities in adult live...

The distribution and biochemical diversity of neuroglial cells in the avian optic tectum were analyzed using immunohistochemical techniques. Polyclonal and monoclonal antibodies were employed to define the distributions and localizations of four proteins that are considered to be glial-specific in the mammalian central nervous system: glutamine synthetase, carbonic anhydrase-C, glial fibrillary...

The hydrocortisone-mediated induction of glutamine synthetase in the neural retina of chicken embryo in vitro is correlated with enhanced incorporation into protein of [(14)C]aspartic acid, an amino acid abundant in this enzyme. In the induced retina labeled with [(14)C]aspartic acid, a peak of radioactivity was detected in the region of the polysomal profile corresponding to polysomes comprisi...