The Properties of Firefly Luciferase from Lucoila Chinesis L

Recent years,Bioluminescence which was catalyzed by firefly lueiferase involving lueiferin and ATP has been widely applied into the detection of ATP,counting of bacterium,environmental protection,new drugs screening and other biology researches.The firefly lueiferase in this research was extracted in Lucoila Chinesis L from ZheJiang province.Lucoila Chinesis L was a particular firefly which only inhabited in china mainland. First,Enzymology properties of firefly luciferase from Lucoila Chinesis L in this research was investigated that:Its relatively molecular mass was 6 400,Dynamic studies showed that it didn t behave characteristic of the typical Meehaelis-Menten enzyme.Both the dynamic curve for ATP and luciferin indicated an S shape. The optimum pH and temperature for the reaction involved the firefly luciferase were 6.5 and 20～25℃, respectively,and the activity of the firefly luciferase completely lost when the reaction temperature is above 30℃.This phenomenon indicated that the firefly luciferase was sensitive to the change of temperature. Second,some spectral characteristics also investigated.The wave length in the peak of light emission re- leased from the reaction catalyzed by this firefly lueiferase did not demonstratedred shiftphenomena when pH value dropped.Mg~(2+) and Mn~(2+) did the same thing when activating the firefly luciferase to a certain extent, while the Ca~(2+) did the 50% effect that Mg~(2+) or Mn~(2+) did.Like the Hg~(2+) and Cd~(2+),the Cu~(2+) can inhibit the activity of firefly luciferase in a certain degree.The firefly luciferase's stability was weaker and it was very sen- sitive to the sun light and salt of high concentration.GSH and DTT were very useful in protecting the activity of the enzyme which can keep the activity of firefly luefferase during certain periods,and the GSH did a better job than the DTT did in protecting and enhencing the stability of this firefly luciferase under the same circum- stance.