| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1993: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1992: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
To elucidate the mechanism of pressure-induced reactivation of inactivated enzymes, the pressure effects on the activity of some food related enzymes were studied under pressures up to 3000 atm. (1) Catalase (tetramer, residual activity 60%) inactivated by pressuring at 3000 atm was reactivated, to at most 100%, by pressuring again at 1000-2000 atm for 10 min. Pressure-induced reactivation was not observed for freeze-thawing, freeze-drying and heat-denatured enzyme. (2) beta-galactosidase showed reversible pressure inactivation under 2500 atm but the specific activity was elevated after release of pressure. The repeating pressurization at 500 atm increased the activity at most two-fold. These results suggest that the rate processes of dissociation-association equiribrium (tetramer(〕SY.dblharw.〔)dimer(〕SY.dblharw.〔)monomer) of this enzyme as well as catalase are affected by pressure to drift the equilibrium to active form (tetramer). (3) Aldolase and malatedehydrogenase inactivated by pressure and heat were not reactivated by re-pressurization while both enzymes were also oligomeric ones. Monomeric enzymes, lipase and peroxidase were also not reactivated by pressure.
Based on these results, the pressure-induced reactivation of enzymes seems to be phenomena under limited conditions, but the drift of structure (dissociation-association equilibrium) would be responsible for the reactivation by pressure.
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