Temperature and the regulation of enzyme activity in poikilotherms. Regulatory properties of fructose diphosphatase from muscle of the Alaskan king-crab
1. The properties of fructose diphosphatase from skeletal muscle of the Alaskan king-crab (Paralithodes camtschatica) were examined over the physiological temperature range of the animal. 2. King-crab muscle fructose diphosphatase is first activated by Na+ and NH4+ and is then partially inhibited by...
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Portland Press Ltd.
1971
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crportlandpress:10.1042/bj1210399 2024-06-09T07:37:57+00:00 Temperature and the regulation of enzyme activity in poikilotherms. Regulatory properties of fructose diphosphatase from muscle of the Alaskan king-crab Behrisch, Hans W. 1971 http://dx.doi.org/10.1042/bj1210399 https://portlandpress.com/biochemj/article-pdf/121/3/399/769945/bj1210399.pdf en eng Portland Press Ltd. Biochemical Journal volume 121, issue 3, page 399-409 ISSN 0306-3283 journal-article 1971 crportlandpress https://doi.org/10.1042/bj1210399 2024-05-16T14:10:08Z 1. The properties of fructose diphosphatase from skeletal muscle of the Alaskan king-crab (Paralithodes camtschatica) were examined over the physiological temperature range of the animal. 2. King-crab muscle fructose diphosphatase is first activated by Na+ and NH4+ and is then partially inhibited by these cations at concentrations higher than 10mm at 0°, 8° and 15°C. Enzyme activity is stimulated by K+ at 0°C, but is curtailed at 8°C and 15°C, an effect that could render rate independent of temperature. 3. Affinity for substrate increases with decreasing temperature; below the temperature of acclimatization, Km for fructose 1,6-diphosphate increases, resulting in a complex U-shaped temperature–Km curve. 4. King-crab muscle fructose diphosphatase is inhibited by low concentrations of AMP. As with enzymes of other poikilotherms, inhibition by AMP is sensitive to temperature; the enzyme is least sensitive to inhibition by AMP near the temperature of acclimatization. 5. The affinity of fructose diphosphatase for fructose 1,6-diphosphate is enhanced by phosphoenolpyruvate, and this activation is temperature-sensitive; 0.5mm-phosphoenolpyruvate causes a sevenfold decrease in Km for fructose 1,6-diphosphate at 15°C but a 25-fold decrease at 0°C. 6. Phosphoenolpyruvate appears to decrease the affinity of king-crab muscle fructose diphosphatase for AMP at low temperature, whereas at the higher temperature it appears to enhance inhibition by AMP. Phosphoenolpyruvate was not observed to cause a reversal of inhibition of fructose diphosphatase activity by AMP. The identification of phosphoenolpyruvate as an activator of a rate-limiting step in gluconeogenesis permits the suggestion of a coupling of the controlling mechanisms of several steps in the glycolytic and gluconeogenic chains. 7. These findings suggest mechanisms for the maintenance and regulation of control of fructose diphosphatase activity in king-crab skeletal muscle at low temperature and under conditions that favour concomitant activity of phosphofructokinase. Article in Journal/Newspaper Alaskan king crab Portland Press Biochemical Journal 121 3 399 409 |
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English |
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1. The properties of fructose diphosphatase from skeletal muscle of the Alaskan king-crab (Paralithodes camtschatica) were examined over the physiological temperature range of the animal. 2. King-crab muscle fructose diphosphatase is first activated by Na+ and NH4+ and is then partially inhibited by these cations at concentrations higher than 10mm at 0°, 8° and 15°C. Enzyme activity is stimulated by K+ at 0°C, but is curtailed at 8°C and 15°C, an effect that could render rate independent of temperature. 3. Affinity for substrate increases with decreasing temperature; below the temperature of acclimatization, Km for fructose 1,6-diphosphate increases, resulting in a complex U-shaped temperature–Km curve. 4. King-crab muscle fructose diphosphatase is inhibited by low concentrations of AMP. As with enzymes of other poikilotherms, inhibition by AMP is sensitive to temperature; the enzyme is least sensitive to inhibition by AMP near the temperature of acclimatization. 5. The affinity of fructose diphosphatase for fructose 1,6-diphosphate is enhanced by phosphoenolpyruvate, and this activation is temperature-sensitive; 0.5mm-phosphoenolpyruvate causes a sevenfold decrease in Km for fructose 1,6-diphosphate at 15°C but a 25-fold decrease at 0°C. 6. Phosphoenolpyruvate appears to decrease the affinity of king-crab muscle fructose diphosphatase for AMP at low temperature, whereas at the higher temperature it appears to enhance inhibition by AMP. Phosphoenolpyruvate was not observed to cause a reversal of inhibition of fructose diphosphatase activity by AMP. The identification of phosphoenolpyruvate as an activator of a rate-limiting step in gluconeogenesis permits the suggestion of a coupling of the controlling mechanisms of several steps in the glycolytic and gluconeogenic chains. 7. These findings suggest mechanisms for the maintenance and regulation of control of fructose diphosphatase activity in king-crab skeletal muscle at low temperature and under conditions that favour concomitant activity of phosphofructokinase. |
format |
Article in Journal/Newspaper |
author |
Behrisch, Hans W. |
spellingShingle |
Behrisch, Hans W. Temperature and the regulation of enzyme activity in poikilotherms. Regulatory properties of fructose diphosphatase from muscle of the Alaskan king-crab |
author_facet |
Behrisch, Hans W. |
author_sort |
Behrisch, Hans W. |
title |
Temperature and the regulation of enzyme activity in poikilotherms. Regulatory properties of fructose diphosphatase from muscle of the Alaskan king-crab |
title_short |
Temperature and the regulation of enzyme activity in poikilotherms. Regulatory properties of fructose diphosphatase from muscle of the Alaskan king-crab |
title_full |
Temperature and the regulation of enzyme activity in poikilotherms. Regulatory properties of fructose diphosphatase from muscle of the Alaskan king-crab |
title_fullStr |
Temperature and the regulation of enzyme activity in poikilotherms. Regulatory properties of fructose diphosphatase from muscle of the Alaskan king-crab |
title_full_unstemmed |
Temperature and the regulation of enzyme activity in poikilotherms. Regulatory properties of fructose diphosphatase from muscle of the Alaskan king-crab |
title_sort |
temperature and the regulation of enzyme activity in poikilotherms. regulatory properties of fructose diphosphatase from muscle of the alaskan king-crab |
publisher |
Portland Press Ltd. |
publishDate |
1971 |
url |
http://dx.doi.org/10.1042/bj1210399 https://portlandpress.com/biochemj/article-pdf/121/3/399/769945/bj1210399.pdf |
genre |
Alaskan king crab |
genre_facet |
Alaskan king crab |
op_source |
Biochemical Journal volume 121, issue 3, page 399-409 ISSN 0306-3283 |
op_doi |
https://doi.org/10.1042/bj1210399 |
container_title |
Biochemical Journal |
container_volume |
121 |
container_issue |
3 |
container_start_page |
399 |
op_container_end_page |
409 |
_version_ |
1801382371389341696 |