Catalytic activity of thermolysin under extremes of pressure and temperature: modulation by metal ions.
The catalytic activity of thermolysin (TL), a Zn-dependent neutral protease from Bacillus thermoproteolyticus, has been studied over a wide interval of pressures (1 bar to 4 kbar) and temperatures (20 degreesC to 80 degreesC) by monitoring hydrolysis of a low-molecular-mass substrate, 3-(2-furylacryloyl)-glycyl-L-leucine amide. This reaction shows a very large negative value for the activation volume and, because of that, simultaneous increase in temperature and pressure leads to a significant (up to 40-fold) acceleration of the reaction. At pressures higher than 2-2.5 kbar, the reaction rate starts to decrease due to disactivation of TL. This disactivation is explained in part by pressure-promoted dissociation of zinc ion from the active site and can be inhibited by adding exogenous zinc. Thus, this thermostable protease does not specifically show a higher stability at high pressure in comparison with small mesophilic proteases.
Chemistry Department, Moscow State University, 119899 Moscow, Russia.
E V
EV
Kudryashova
V V
VV
Mozhaev
C
C
Balny
D000179:Acrylates / Q000378:metabolism; D001407:Bacillus / Q000201:enzymology; D002118:Calcium / Q000494:pharmacology; D002413:Cations, Divalent / Q000494:pharmacology; D003035:Cobalt; D004151:Dipeptides / Q000378:metabolism; D004795:Enzyme Stability; D006358:Hot Temperature; D006868:Hydrolysis; D006874:Hydrostatic Pressure; D008956:Models, Chemical; D011487:Protein Conformation; D013820:Thermolysin / Q000187:drug effects / Q000378:metabolism*; D015032:Zinc / Q000494:pharmacology*
D000179:Acrylates; D002413:Cations, Divalent; D004151:Dipeptides; C108649:N-(3-(2-furyl)acryloyl)glycyl-leucinamide; D003035:Cobalt; D013820:Thermolysin; D015032:Zinc; D002118:Calcium