Biochemical and molecular characterization of a detergent stable alkaline serine-protease from a newly isolated Bacillus licheniformis NH1

2007 ◽  
Vol 40 (4) ◽  
pp. 515-523 ◽  
Author(s):  
Nedra El Hadj-Ali ◽  
Rym Agrebi ◽  
Basma Ghorbel-Frikha ◽  
Alya Sellami-Kamoun ◽  
Safia Kanoun ◽  
...  
Keyword(s):  
Serine Protease ◽  
Molecular Characterization ◽  
Bacillus Licheniformis ◽  
Alkaline Serine Protease

scholarly journals Molecular characterization of centerin, a germinal centre cell serpin

2007 ◽  
Vol 405 (3) ◽  
pp. 489-494 ◽  
Author(s):  
Melinda A. Paterson ◽  
Anita J. Horvath ◽  
Robert N. Pike ◽  
Paul B. Coughlin
Keyword(s):  
B Cell ◽  
Serine Protease ◽  
Molecular Characterization ◽  
Good Prognosis ◽  
Germinal Centre ◽  
Lymphoid Malignancies ◽  
B Cell Maturation ◽  
Absolute Requirement

Centerin [SERPINA9/GCET1 (germinal centre B-cell-expressed transcript 1)] is a serpin (serine protease inhibitor) whose expression is restricted to germinal centre B-cells and lymphoid malignancies with germinal centre B-cell maturation. Expression of centerin, together with bcl-6 and GCET2, constitutes a germinal centre B-cell signature, which is associated with a good prognosis in diffuse large B-cell lymphomas, but the molecular basis for this remains to be elucidated. We report here the cloning, expression and molecular characterization of bacterial recombinant centerin. Biophysical studies demonstrated that centerin was able to undergo the ‘stressed to relaxed’ conformational change which is an absolute requirement for protease inhibitory activity. Kinetic analysis showed that centerin rapidly inhibited the serine protease trypsin (ka=1.9×105 M−1·s−1) and also demonstrated measurable inhibition of thrombin (ka=1.17×103 M−1·s−1) and plasmin (ka=1.92×103 M−1·s−1). Centerin also bound DNA and unfractionated heparin, although there was no functionally significant impact on the rate of inhibition. These results suggest that centerin is likely to function in vivo in the germinal centre as an efficient inhibitor of a trypsin-like protease.

scholarly journals Purification and Biochemical Characterization of Alkaline Serine Protease from Caesalpinia bonducella

2010 ◽  
Vol 5 (6) ◽  
pp. 1934578X1000500
Author(s):  
Hidayatullah Khan ◽  
Irshad Ali ◽  
Arif-ullah Khan ◽  
Mushtaq Ahmed ◽  
Zamarud Shah ◽  
...  
Keyword(s):  
Serine Protease ◽  
Biochemical Characterization ◽  
Specific Activity ◽  
Sodium Dodecyl ◽  
Exchange Chromatography ◽  
Size Exclusion ◽  
Alkaline Serine Protease ◽  
Protease Enzyme ◽  
Caesalpinia Bonducella

A high molecular weight serine protease has been purified to electrophoretic homogeneity from the seeds of Caesalpinia bonducella Flem. (Caesalpiniaceae) by the combination of size exclusion and ion exchange chromatography. About 524 fold purification was achieved with an overall recovery of 6.8%. The specific activity was found to be 86 U/mg/min at pH 8.0. The calculated Km and Vmax were 1.66 mg/mL and 496.68 units/min per mg of protein, respectively. The molecular mass was estimated to be about 63 kDa by sodium dodecyl sulfate PAGE. The enzyme showed optimum activity at pH 8.0 and exhibited its highest activity at 40°C. The enzyme was strongly inhibited by 2mM phenylmethylsulfonyl fluoride (PMSF), suggesting the presence of a serine residue at the active site. PMSF showed a pure competitive type of inhibition with the serine protease enzyme. It was observed that enzyme activity was enhanced in the presence of dications and was active against a variety of modified substrates and natural proteins.

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