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https://hdl.handle.net/10316/13030
Title: | Effect of temperature on the reversal of the calcium ion pump in sarcoplasmic reticulum | Authors: | Vale, M. G. P. Carvalho, A. P. |
Issue Date: | 15-Feb-1980 | Publisher: | Portland Press | Citation: | Biochemical Journal. 186:2 (1980) 461-467 | Serial title, monograph or event: | Biochemical Journal | Issue: | 186:2 | Abstract: | Sarcoplasmic-reticulum vesicles were actively loaded with Ca2+ in the presence of phosphate, and the ADP-induced Ca2+ efflux and ATP synthesis were measured as a function of temperature. Arrhenius plots show break points for both processes at about 18 and 37 degrees C. Between 18 and 37 degrees C, Ca2+ efflux and ATP synthesis occur with an activation energy of 67.2-71.4 kJ/mol, whereas it is about 189-210 kJ/mol for temperatures below 18 degrees C. Above 37 degrees C, the rates of ADP-induced Ca2+ release and of ATP synthesis sharply decline until the temperature reaches about 42 degrees C. Above this temperature, the Ca2+ efflux increases again even in absence of ADP, although the synthesis of ATP is inhibited, which reflects leakiness of the vesicles. The results show that the transition temperatures for ADP-induced Ca2+ efflux and for ATP synthesis resemble those for active Ca2+ uptake, which indicates that the same coupling mechanism is involved during the inward and outward Ca2+ translocations across the membrane | Description: | Biochemical Journal. 186:2 (1980) 461-467 | URI: | https://hdl.handle.net/10316/13030 | ISSN: | 0306-3283 | DOI: | 10.1042/bj1860461 | Rights: | openAccess |
Appears in Collections: | FCTUC Ciências da Vida - Artigos em Revistas Internacionais |
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Effect of temperature on the reversal.pdf | 946 kB | Adobe PDF | View/Open |
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