Enzyme kinetics in acoustically levitated droplets of supercooled water: a novel approach to cryoenzymology.
The rate of the alkaline phosphatase-catalyzed hydrolysis of 4-methylumbelliferone phosphate was measured in acoustically levitated droplets of aqueous tris (50 mM) at pH 8.5 at 22 +/- 2 degrees C and in supercooled solution at -6 +/- 2 degrees C. At 22 degrees C, the rate of product formation was in excellent agreement with the rate observed in bulk solution in a cuvette, indicating that the acoustic levitation process does not alter the enzyme activity. The rate of the reaction decreased 6-fold in supercooled solution at -6 +/- 2 degrees C. The acoustic levitator apparatus is described in detail.
Weis
David D
DD
Department of Chemistry, Skidmore College, 815 North Broadway, Saratoga Springs, New York 12866-1632, USA. dweis@unm.edu
Nardozzi
Jonathan D
JD
D000162:Acoustics / Q000295:instrumentation*; D000469:Alkaline Phosphatase / Q000737:chemistry / Q000378:metabolism; D002138:Calibration; D004798:Enzymes / Q000737:chemistry* / Q000378:metabolism; D004867:Equipment Design; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D006923:Hymecromone / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D013050:Spectrometry, Fluorescence / Q000295:instrumentation / Q000379:methods; D013696:Temperature; D014867:Water / Q000737:chemistry*
D004798:Enzymes; D014867:Water; D006923:Hymecromone; D000469:Alkaline Phosphatase