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Biomedical subjects

R Palacios

Publications and source records attributed to R Palacios.

At least 199 records · Page 11Linked to original sources

Neurospora crassa glutamine synthetase. Role of enzyme synthesis and degradation on the regulation of enzyme concentration during exponential growth.

The specific activity of Neurospora crassa glutamine synthetase varies according to the nitrogen source in which the organism is grown. In a poor nitrogen source such as glutamate, the specific activity of the enzyme is higher than that found in good nitrogen sources such as ammonium or glutamine. These differences in specific enzyme activity correspond to differences in enzyme concentration. The relative rates of glutamine synthetase synthesis and degradation were measured in exponential cultures grown in different nitrogen sources. The differences in enzyme concentration are explained by differences in the relative rate of enzyme synthesis.

Ammonia↗

Neurospora crassa glutamine synthetase. Translation of specific messenger ribonucleic acid in a cell-free system derived from rabbit reticulocytes.

The total reticulocyte lysate cell-free protein-synthesizing system was incubated in the presence of Neurospora crassa RNA. With the aid of an antibody directed against purified N. crassa glutamine synthetase, the synthesis of a specific protein was detected. This protein precipitates with antiglutamine synthetase using both direct and indirect procedures, migrates with the same molecular weight as the monomer of N. crassa glutamine synthetase when subjected to acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, and chromatographs as N. crassa glutamine synthetase on anthranilate-bound Sepharose. These data indicate the translation of the mRNA that codes for N. crassa glutamine synthetase. This RNA behaves as poly(A)-containing material when fractionated on oly(U)-Sepha-rose.

Animals↗

Neurospora crassa glutamine synthetase. Purification by affinity chromatography and characterization of subunit structure.

Neurospora crassa glutamine synthetase was purified to homogeneity by a procedure based on affinity chromatography. The enzyme is adsorbed to a matrix of anthranilic acid bound to Sepharose and eluted with AMP. Different experimental approaches indicate that the enzyme has an octameric structure formed by subunits of identical molecular weight.

Chromatography, Affinity↗