EC Number   |
Application |
Reference |
|---|
    4.2.3.27 | analysis |
development of a method to measure the isopentenyl diphosphate levels and the ratio of dimethyallyl diphosphate/isopentenyl diphosphate in bacteria and plant tissues. The amount of dimethyallyl diphosphate is measured by conversion to isoprene using isoprene synthase IspS, and the total amount of dimethyallyl diphosphate plus isopentenyl diphosphate is measured by including isopentenyldiphosphate isomerase IDI in the assay mixture. The in vitro equilibrium ratio of dimethylallyl diphosphate/isopentenyl diphosphate is 2.11:1. Isopentenyl diphosphate and dimethylallayl diphosphate pools are significantly increased in Escherichia coli transformed with methylerythritol 4-phosphate pathway genes; the ratio dimethyallyl diphosphate/isopentenyl diphosphate is 3.85. An Escherichia coli strain transformed with IspS but no additional IDI has a lower dimethylallyl diphosphate level and a dimethyallyl diphosphate/isopentenyl diphosphate ratio of 1.05 |
726676 |
| 4.2.3.27 | analysis |
method for measuring isoprene emission based on postillumination isoprene release after rapid temperature transient, and application to determine the rate constant of isoprene synthase, the pool size of its substrate dimethylallyldiphosphate, and to separate the component processes of the temperature dependence of isoprene emission |
716604 |
| 4.2.3.27 | environmental protection |
analysis of in vivo isoprene emission. The in vivo rate constant of IspS obeys the Arrhenius law, with an activation energy of 42.8 kJ per mol. Steady-state isoprene emission has a significantly lower temperature optimum than IspS and higher activation energy. The reversible temperature-dependent decrease in the rate of isoprene emission between 35°C and 44°C is caused by decreases in dimethylallyl diphosphate concentration, possibly reflecting reduced pools of energetic metabolites generated in photosynthesis, particularly of ATP. Strong control of isoprene temperature responses by the dimethylallyl diphosphate pool implies that transient temperature responses under fluctuating conditions in the field are driven by initial dimethylallyl diphosphate pool size as well as temperature-dependent modifications in dimethylallyl diphosphate pool size during temperature transients |
716604 |
| 4.2.3.27 | environmental protection |
isoprene emission patterns in transgenic tobacco plants are remarkably similar to naturally emitting plants under a wide variety of conditions. Emissions correlate with photosynthetic rates in developing and mature leaves, and with the amount of isoprene synthase protein in mature leaves. Isoprene synthase protein levels do not change under short-term increase in heat/light, despite an increase in emissions under these conditions. A robust circadian pattern can be observed in emissions from long-day plants. Substrate supply and changes in enzyme kinetics rather than changes in isoprene synthase levels or post-translational regulation of activity seem to be the primary controls on isoprene emission in mature transgenic tobacco leaves |
716488 |
| 4.2.3.27 | environmental protection |
regulation of isoprene emission. Upon darkening a leaf, isoprene emission falls nearly to zero but then increases for several min before falling back to nearly zero. Time of appearance of this burst of isoprene is highly temperature dependent, occurring sooner at higher temperatures. During a rapid temperature switch from 30°C to 40°C, isoprene emission increases transiently with concomitant increase in isoprene synthase activity, while dimethylallyl diphosphate level stays constant during the switch. One h after switching to 40!, the amount of dimethylallyl diphosphate falls but the rate constant for isoprene synthase remains constant, indicating that the high temperature falloff in isoprene emission results from a reduction in the supply of dimethylallyl diphosphate rather than from changes in isoprene synthase activity |
716610 |
| 4.2.3.27 | synthesis |
construction of a synthetic pathway of isoprene in Escherichia coli by introducing an isoprene synthase gene from Populus nigra and overexpression of the native or Bacillus subtilis 1-deoxy-D-xylulose-5-phosphate synthase gene and 1-deoxy-D-xylulose-5-phosphate reductoisomerase gene. Transformants expressing ispS alone accumulate around 94 mg isoprene per liter of broth.Transformants expressing ispS plus the native 1-deoxy-D-xylulose-5-phosphate synthase gene and 1-deoxy-D-xylulose-5-phosphate reductoisomerase gene produce 160 mg isoprene per liter. Transformants expressing ispS plus Bacillus subtilis 1-deoxy-D-xylulose-5-phosphate synthase gene and 1-deoxy-D-xylulose-5-phosphate reductoisomerase gene produce 314 mg isoprene per liter |
713907 |
| 4.2.3.27 | synthesis |
heterologous expression of the isoprene synthase gene in the cyanobacterium Synechocystis PCC 6803 in combination with mevalonate pathway enzymes results in photosynthetic isoprene yield improvement by approximately 2.5fold, compared with that measured in cyanobacteria transformed with the isoprene synthase gene only. The mevalonate pathway introduces a bypass in the flux of endogenous cellular substrate in Synechocystis to isopentenyl diphosphate and dimethylallyl diphosphate, overcoming flux limitations of the native methylerythritol-phosphate pathway |
730429 |
| 4.2.3.27 | synthesis |
production of isoprene in Escherichia coli by improvement of the efficiency of the mevalonate pathway and expression of isoprene synthase. The final genetic strain containing the optimized mevalonate pathway and isoprene synthase from Populus alba can accumulate isoprene up to 6.3 g/l after 40 h of fed-batch cultivation |
730690 |
