In Vitro Amidating Processing of Products Expressed by Gene Engineering

Area of Science:

• Biochemistry
• Molecular Biology
• Protein Chemistry

Background:

• Peptide amidation is a crucial post-translational modification.
• Establishing efficient in vitro systems for peptide modification is essential for research and therapeutic applications.
• Recombinant human calcitonin (mhCT-Gly) and peptidylglycine alpha-amidating monooxygenase (rPAM) are key components in this study.

Purpose of the Study:

• To establish an in vitro amidating system for recombinant proteins.
• To utilize recombinant rat peptidylglycine alpha-amidating monooxygenase (rPAM) for substrate modification.
• To develop a method for detecting the amidated product, GST-hCT-NH(2).

Main Methods:

• Synthesis and cloning of the mhCT-Gly gene into a pGEXCT expression vector.
• High-level expression and purification of GST-fused mhCT-Gly in E. coli.
• Preparation of rPAM from cultured CHO cells using ultrafiltration.
• In vitro amidation assays using purified GST-mhCT-Gly and rPAM.
• Detection of the amidated product via dot blot and mass spectrometry.

Main Results:

• Successful high-level expression and rapid purification of GST-mhCT-Gly.
• Efficient preparation of rPAM from stable transfectant CHO cell cultures.
• Confirmation of the amidating reaction by detecting the GST-hCT-NH(2) product using specific antibodies and mass spectrometry.

Conclusions:

• An effective in vitro system for the amidation of recombinant calcitonin was successfully established.
• The developed method allows for the detection of the amidated product, GST-hCT-NH(2).
• This study provides a valuable method for in vitro amidation of recombinant products.