Purification and characterization of a novel thermostable luciferase from Benthosema pterotum

• A novel thermostable luciferase from Benthosema pterotum (BP) was purified.
• The molecular mass of novel enzyme is about 27 kDa and its Km value is 0.4 ± 0.01 μM.
• BP luciferase showed maximum intensity of emitted light at 40 °C, pH 9 and 30 mM magnesium.
• BP luciferase is a thermostable enzyme and it shows a high activity at extreme pH values.
• BP luciferases generated blue light with a maximum emission wavelength at 475 nm.

A novel luciferase from Benthosema pterotum, collected from Port of Jask, close to Persian Gulf, was purified for the first time, using Q-Sepharose anion exchange chromatography. The molecular mass of the novel enzyme, measured by SDS–PAGE technique, was about 27 kDa and its Km value is 0.4 μM; both values are similar to those of other coelenterazine luciferases. B. pterotum (BP) luciferase showed maximum intensity of emitted light at 40 °C, in 20 mM Tris buffer, pH 9 and 20 mM magnesium concentration. Experimental measurements indicated that BP luciferase is a relatively thermostable enzyme; furthermore it shows a high residual activity at extreme pH values. Its biological activity is strongly inhibited by 1 mM Cu2+, Zn2+ and Ni2+, while calcium and mainly magnesium ions strongly increase BP luciferase activity. The B. pterotum luciferase generated blue light with a maximum emission wavelength at 475 nm and showed some similarity with other luciferases, while other parameters appeared quite different, in this way, confirming that a novel protein has been purified.