Expression and characterization of recombinant human micro-plasminogen

Area of Science:

• Biochemistry
• Molecular Biology
• Protein Engineering

Background:

• Plasminogen activation is crucial for fibrinolysis.
• Understanding micro-plasminogen (microPlg) function requires efficient recombinant production.
• The role of specific plasminogen domains in enzyme activation is not fully elucidated.

Purpose of the Study:

• To express and purify recombinant human micro-plasminogen (rh-microPlg).
• To compare the activation kinetics of rh-microPlg and Glu-plasminogen by urokinase (UK).
• To investigate the catalytic efficiency of recombinant human micro-plasmin (rh-microPlm) and Lys-plasmin in pro-urokinase (proUK) activation.

Main Methods:

• Reverse transcription PCR amplification of microPlg gene from human liver cells.
• Insertion into pET-28a vector and transformation into E. coli BL21(DE3) for expression.
• IPTG-induced over-expression, renaturation, purification, and enzymatic activity assays.

Main Results:

• Successfully produced 16 mg/l of 95% pure rh-microPlg.
• UK activation of rh-microPlg was significantly faster than Glu-plasminogen.
• Lys-plasmin showed a fourfold greater catalytic efficiency in proUK activation compared to rh-microPlm.

Conclusions:

• The kringle 1-5 domain of plasminogen/plasmin plays a role in modulating UK-mediated plasminogen activation.
• This domain also influences plasmin-mediated proUK activation.
• rh-microPlg is a valuable tool for studying plasminogen activation pathways.