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Estimation of the fructose diphosphatase-phosphofructokinase substrate cycle in the flight muscle of Bombus affinis.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Clark, Michael G. Bloxham, David P. Holland, Paul C. Lardy, Henry A. |
| Copyright Year | 1973 |
| Abstract | 1. Substrate cycling of fructose 6-phosphate through reactions catalysed by phosphofructokinase and fructose diphosphatase was estimated in bumble-bee (Bombus affinis) flight muscle in vivo. 2. Estimations of substrate cycling of fructose 6-phosphate and of glycolysis were made from the equilibrium value of the (3)H/(14)C ratio in glucose 6-phosphate as well as the rate of (3)H release to water after the metabolism of [5-(3)H,U-(14)C]glucose. 3. In flight, the metabolism of glucose proceeded exclusively through glycolysis (20.4mumol/min per g fresh wt.) and there was no evidence for substrate cycling. 4. In the resting bumble-bee exposed to low temperatures (5 degrees C), the pattern of glucose metabolism in the flight muscle was altered so that substrate cycling was high (10.4mumol/min per g fresh wt.) and glycolysis was decreased (5.8mumol/min per g fresh wt.). 5. The rate of substrate cycling in the resting bumble-bee flight muscle was inversely related to the ambient temperature, since at 27 degrees , 21 degrees and 5 degrees C the rates of substrate cycling were 0, 0.48 and 10.4mumol/min per g fresh wt. respectively. 6. Calcium ions inhibited fructose diphosphatase of the bumble-bee flight muscle at concentrations that were without effect on phosphofructokinase. The inhibition was reversed by the presence of a Ca(2+)-chelating compound. It is proposed that the rate of fructose 6-phosphate substrate cycling could be regulated by changes in the sarcoplasmic Ca(2+) concentration associated with the contractile process. |
| File Format | PDF HTM / HTML |
| DOI | 10.1042/bj1340589 |
| PubMed reference number | 16742821 |
| Journal | Medline |
| Volume Number | 134 |
| Issue Number | 2 |
| Alternate Webpage(s) | http://www.biochemj.org/content/ppbiochemj/134/2/589.full.pdf |
| Alternate Webpage(s) | https://doi.org/10.1042/bj1340589 |
| Journal | The Biochemical journal |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
