Evidence for Reversible Inactivation of Induced Tyrosine Aminotransferase in Rat Liver In Vivo
Autor: | Amal Boctor, Albert Grossman |
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Rok vydání: | 1972 |
Předmět: |
Male
Hydrocortisone Biology Cycloheximide chemistry.chemical_compound Tyrosine aminotransferase Antibody Specificity Polysome Protein biosynthesis Animals Peptide Chain Initiation Translational Tyrosine Transaminase chemistry.chemical_classification Carbon Isotopes Multidisciplinary Adrenalectomy Rats Inbred Strains Molecular biology Enzyme assay Rats Amino acid Enzyme Activation Enzyme Liver chemistry Biochemistry Puromycin Enzyme Induction Antibody Formation biology.protein Biological Sciences: Biochemistry Ribosomes Protein Binding |
Zdroj: | Proceedings of the National Academy of Sciences. 69:1161-1164 |
ISSN: | 1091-6490 0027-8424 |
DOI: | 10.1073/pnas.69.5.1161 |
Popis: | Induction of tyrosine aminotransferase (EC 2.6.1.5) with cortisol is followed by a rapid phase of inactivation of the enzyme, during which administration of puromycin causes a sharp increase in enzyme activity. The increase is not due to puromycin-resistant synthesis of protein, since precipitation of the enzyme with antibodies to tyrosine aminotransferase after pulse labeling inhibited incorporation of radioactive amino acids. Reactivation of the enzyme was specific, since the structurally similar dimethylaminopurine and purine aminonucleoside were ineffective. An action of puromycin other than its capacity to inhibit protein synthesis was required for reactivation, since cycloheximide did not demonstrate such an effect. In vitro studies with free and bound polysomes, isolated during the phase of inactivation, indicated that reactivation by puromycin was not due to release of nascent tyrosine aminotransferase peptides. We conclude that the enzyme is initially reversibly inactivated; therefore, the overall degradation of this intracellular protein is a multistep phenomenon. |
Databáze: | OpenAIRE |
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