Catalytic and thermodynamic characterization of protease from Halobacterium sp. SP1(1).

Autor: Akolkar AV; Department of Microbiology and Biotechnology Centre, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara 390002, India., Desai AJ
Jazyk: angličtina
Zdroj: Research in microbiology [Res Microbiol] 2010 Jun; Vol. 161 (5), pp. 355-62. Date of Electronic Publication: 2010 May 15.
DOI: 10.1016/j.resmic.2010.04.005
Abstrakt: Osmolytes KCl, glycerol, mannitol, trehalose, sucrose, betaine, proline and Na-glutamate at different concentrations (5-30%) were investigated as effective solutes for retaining the activity of Halobacterium sp. SP1(1) protease in the absence of NaCl. Maximum activity was observed in the presence of 30% Na-glutamate. Kinetic and thermodynamic parameters for casein hydrolysis revealed that the protease was equally efficient in the presence of Na-glutamate as in NaCl. The enzyme was active over a broader range of temperature (20-80 degrees C) and was highly stable even at 80 degrees C with Na-glutamate. Thermodynamic parameters (DeltaH*, DeltaS*, G*) for irreversible inactivation of protease at different temperatures (20-80 degrees C) were determined in the presence of Na-glutamate and NaCl. The efficiency of these osmolytes for thermal stability of protease was 30% (1.6 M) Na-glutamate > 4 M ( approximately 25%) NaCl > 2 M (approximately 10%), suggesting that the effect exerted by the osmolyte depends not only on its chemical nature but also on its concentration. Na-glutamate was thus found to play an important role in thermal stabilization of enzyme substituting for NaCl. Moreover, substitution of NaCl by Na-glutamate may increase the applicability of halophilic enzymes in biotechnology and industry, which is otherwise limited to high NaCl concentrations.
(2010 Elsevier Masson SAS. All rights reserved.)
Databáze: MEDLINE
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