Mouse Macrophage Metalloelastase Expressed in Bacteria Absolutely Requires Zinc for Activity.

概要

論文の詳細を見る
Mouse macrophage metalloelastase was expressed in Escherichia coli. This recombinant enzyme (rMME) was present in the inclusion bodies that were solubilized in 7M guanidine HCl. After removal of guanidine HCl, rMME was purified with a Q-Sepharose column. Degradation of [3H]elastin by rMME absolutely required Ca2+; the optimal Ca2+ concentration was 5mM. NaCI stimulated the enzyme activity; maximal stimulation was obtained at 400mM. The rMME activity was inhibited by metalloprotease inhibitors, but not by serine, aspartyl, or thiol protease inhibitors. Among the divalent cations tested, only Ba2+ and Sr2+ exhibited marginal stimulation of rMME activity in the absenee of Ca2+. Cu2+, Zn2+, or Cd2+ strongly inhibited rMME activity with IC50 values between 68 and 180 μM, while Mg2+, Ba2+, Mn2+, Co2+, and Sr2+ had no effect. The requirement of Zn2+ for rMME activity was determined. Significant enzyme activity was present in rMME treated with EDTA followed by Q-Sepharose column chromatography. Only when the inclusion bodies were solubilized in the presence of 20mM EDTA, did an enzyme preparation which was absolutely dependent on exogenous Zn2+ for activity result. The optimal Zn2+ concentration for rMME activation was 100 μM. These results indicate that Zn2+ is tightly bound to rMME.
社団法人日本生化学会の論文