Studies on the energy release of rice mitochondria under different conditions by means of microcalorimetry

The thermodynamic and kinetic behaviors of energy release of mitochondria i solated from rice (Oryza sative L.) were studied by using a LKB 2277 Bioact ivity Monitor under different conditions. The thermogenesis curves of energ y release of the rice mitochondria (which had been kept at 0-3 degreesC for 15 h and 40 day before the determination) were determined respectively at 25 and 30 degreesC, and the difference in shape of the thermogenesis curves and thermodynamic and kinetic characteristics were compared. The thermodyn amic and kinetic parameters of energy release of the mitochondria in the th ermogenesis increasing stage have been calculated, and the experimental the rmokinetic equations of the thermogenesis have been established. The result s indicated that the lower the temperature, the slower the energy release o f the rice mitochondria. Both the thermogenesis and the energy release late of the rice mitochondria increased after the mitochondria was kept at lowe r temperature for 40 days. One can use the methods to characterize the abil ity of the rice mitochondria to release energy under different conditions. (C) 2001 Published by Elsevier Science B.V.