Cloning, expression, purification, and characterization of rat MMP-12

Area of Science:

• Biochemistry
• Enzymology
• Molecular Biology

Background:

• Macrophage metalloelastase (MMP-12) is linked to diseases like emphysema, aortic lesions, and cancer.
• Previous studies have successfully cloned and purified MMP-12 from mouse and human macrophages.

Purpose of the Study:

• To express and characterize the full-length and catalytic domain of rat MMP-12 in Escherichia coli.
• To investigate the substrate specificity of the purified rat MMP-12 catalytic domain.

Main Methods:

• Rat MMP-12 catalytic domain was expressed in E. coli, with inclusion bodies refolded and purified using zinc-chelating Sepharose.
• Enzyme activity was characterized, including K(m) and optimal pH determination.
• Natural substrate specificity was assessed using various collagen types, osteonectin, vitronectin, fibronectin, laminin, and albumin.

Main Results:

• The purified rat MMP-12 catalytic domain exhibited high enzymatic activity with a K(m) of 12 microM and optimal pH of 7.5-8.5.
• Rat MMP-12 catalytic domain completely degraded collagen-V and partially degraded collagen-I, but not collagen-IV.
• The enzyme degraded osteonectin, vitronectin, and fibronectin, but not laminin or albumin.
• Significant differences were observed in catalytic properties and substrate specificity compared to human MMP-12.

Conclusions:

• Rat MMP-12 catalytic domain can be successfully expressed, refolded, and purified from E. coli.
• The characterized substrate specificity of rat MMP-12 catalytic domain highlights its distinct enzymatic profile compared to its human counterpart.
• These findings provide a foundation for further research into MMP-12's role in disease pathology and potential therapeutic targeting.