Stimulation of Proteolysis in Thyroid Particles by Thyrotropin
| Autor: | Richard C. Powell, James A. Starrett, William P. Deiss, Kandiah Balasubramaniam, Robert L. Peake |
|---|---|
| Rok vydání: | 1966 |
| Předmět: |
medicine.medical_specialty
Lysis Proteolysis Thyroid Gland Thyrotropin In Vitro Techniques Colloid Dogs Endocrinology Internal medicine medicine Animals Cathepsin Differential centrifugation medicine.diagnostic_test Chemistry Proteolytic enzymes Proteins Hydrogen-Ion Concentration Chromatography Ion Exchange Cathepsins In vitro Biochemistry Particle Lysosomes |
| Zdroj: | Endocrinology. 79:19-27 |
| ISSN: | 1945-7170 0013-7227 |
| DOI: | 10.1210/endo-79-1-19 |
| Popis: | Differential centrifugation of homogenates of prelabeled dog thyroid tissue provides a fraction, sedimenting between 800 and 15,000 Xg, that contains both colloid droplets and lysosomes. When these fractions from control and TSH-stimulated lobes are suspended in 0.45M sucrose, the 131iodoprotein remains largely particle bound over a pH range of 3.6-8.5. Control lobe particles show lysis of the labeled protein as BE131I during these in vitro incubations with peak activity at pH 3.5-4.0, the optimum of lysosomal cathepsin. TSH particles contain more total 131iodoprotein than controls and show not only more BE131I release than controls, but also a greater percentage of the particulate 131I released as BE131I. Furthermore, it is apparent that the lysis of 131iodoprotein in the TSH particles occurs maximally at a higher pH, 4.6-5.0, than in the control particles. When the particles are destroyed with a detergent, Triton X-100, there is inhibition of proteolysis. These studies, in combination with previous obse... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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