Purification, biochemical characterization and performance evaluation of an alkaline serine protease from Aspergillus flavus MTCC 9952 mutant

Purification and characterization of neutral protease from Aspergillus oryzae Y1 isolated from naturally fermented broad beans

“…In the presence of some metals, the activity of the purified protease was varied. Activity was enhanced to 173 and 145% by 0.2 mM Ca 2+ and Mn 2+ , respectively, concurring with the findings of previous studies (Kamran et al 2015 ; Yadav et al 2015 ). Ca 2+ played a significant role in enhancing the activity of most proteases, possibly due to the stabilization of the enzyme in its active conformation, as opposed to its being impacted in the catalytic reaction (Strongin et al 1978 ).…”

“…Additionally, Mn 2+ has been noted to bind to the amino acid residues of the protease side chains and stabilize their conformation without changing the conformation of the protease catalytic site. Yadav et al ( 2015 ) reported that protease activity is increased by Na 2+ (140%) and Fe 2+ (156%) at 2 mM; and, furthermore, that Sn 2+ , Cu 2+ , Pb 2+ and Al 3+ exert stimulating effects at 0.2 mM concentration, however there are few corroborating reports of these findings. In most studies, Cu 2+ has been reported as a strong inhibitor; for example, when adding 1–5 mM Cu 2+ , the protease activity decreases by between 12% to 98% (Divakar et al 2010 ; Yu et al 2011 ; Yadav et al 2015 ; Ferrareze et al 2016 ; Abidi et al 2011 ; Hsiao et al 2014 ; Khaled et al 2011 ).…”

“…Yadav et al ( 2015 ) reported that protease activity is increased by Na 2+ (140%) and Fe 2+ (156%) at 2 mM; and, furthermore, that Sn 2+ , Cu 2+ , Pb 2+ and Al 3+ exert stimulating effects at 0.2 mM concentration, however there are few corroborating reports of these findings. In most studies, Cu 2+ has been reported as a strong inhibitor; for example, when adding 1–5 mM Cu 2+ , the protease activity decreases by between 12% to 98% (Divakar et al 2010 ; Yu et al 2011 ; Yadav et al 2015 ; Ferrareze et al 2016 ; Abidi et al 2011 ; Hsiao et al 2014 ; Khaled et al 2011 ). Protease inhibition by Mg 2+ , Ba 2+ and Zn 2+ were also reported by Norifumi et al ( 2012 ), who suggested that these metal ions chemically react with the protein group in the polypeptide chain of the enzyme, resulting in the loss of protease activity (Kamran et al 2015 ).…”

Optimized production, characterization and application of alkaline proteases from taxonomically assessed microbial isolates from Lonar soda lake, India

“…The effect of selected protease inhibitors (Phenylmethylsulfonyl fluoride and Dithiothreitol), oxidizing agent (H 2 O 2 ), chelator (Na 2 EDTA), surfactants (Tween 20, Tween 80 and Triton X-100), solvents (Methanol, Ethanol, Acetonitrile, Acetone, Diethyl ether and Ethyl acetate), metal ions (Mg 2+ , Mn 2+ , Cu 2+ , Fe 3+ , Zn 2+ , Ba 2+ , Hg 2+ , Ca 2+ and Na + ) and laundry detergents (Ariel™, Surf excel™, Nirma™, Sasa™, Wheel™, Rin™ and Tide™) at their different concentrations on catalytic efficiency of the each partially purified alkaline protease from the selected isolates was determined by pre-incubating them in these chemicals for 1 h at room temperature and residual activities were measured under standard assay conditions. The laundry detergents were boiled for 15 min to denature the enzymes added by the manufacturer, and cooled prior to use (Bhunia et al, 2011;Maruthiah et al, 2013;Pathak and Rathod, 2014;Mokashe et al, 2015;Sathishkumar et al, 2015;Yadav et al, 2015).…”

Purification, Characterization, and Cloning of a Cold-Adapted Protease from Antarctic Janthinobacterium lividum

“…With the addition of 1 mM PMSF, the enzyme retained 45% of activity. PMSF may inhibit enzyme activity by sulfonating the serine residue in the active site of the protease [19]. However, the proteolytic activity of this cold-adapted protease was not completely inhibited by PMSF.…”