Analytical Instrument: Shimadzu PPSQ-31A Automatic Protein and Peptide Sequencer 

I. Main Applications of Protein N-Terminal Sequencing:

1. Samples: Determination of amino acid sequences in protein and peptide samples

2. Advantages: Capable of continuously sequencing more than 60 amino acids

3. Sources: Natural extracts (animal/plant/microbial); synthetic peptides; recombinant proteins, etc.

II. Sample Requirements:

1. Purity: >95 (based on molarity)

2. Concentration: 50–100 pmol (liquid volume limited to 20 μL)

3. Modification/Capping: N-terminus must not be capped

4. Sample Form: Liquid; dry powder; PVDF membrane

5. Absence of Interfering Substances: Proteases; amino acids; amines; salts; acetaldehyde; detergents, etc.

III. Information to Be Provided by the Client:

1. Purity: Purity test results and chromatogram information

2. Modifications: Possible modifications present in the sample

3. Preparation Method: e.g., SDS, HPLC, and other methods

4. Purpose of Verification: To provide the theoretical sequence

5. Apparent Molecular Weight

Other Notes:

1. Shipping Requirements: Use dry ice for cryoprotection

2. Liquid Samples:

Acceptable solvents: Distilled water, TFA aqueous solution, acetic acid aqueous solution, acetonitrile aqueous solution, and trimethylamine aqueous solution.

Prohibited solvents: Ammonium salts, Tris, etc.; salt solutions containing primary or secondary amines; solutions containing SDS

3. Solid Samples:

For dried samples, please first confirm that the solvent used prior to drying did not contain any of the incompatible solvents listed above. If incompatible solvents were present, please inform our testing personnel.

4. PVDF Membranes: Please note the following:

1) Sample Volume: Use 5–8 lanes. For each lane, use the highest concentration sample possible and load the maximum volume (aim to make the bands 2–3 times their normal width).

2) Nitrocellulose membranes: These are resistant to reagents and cannot be used.

3) Buffers used in electrophoresis should be free of glycine as much as possible. If a glycine-containing buffer is used, please inform our testing personnel.

4) Coomassie Brilliant Blue (CBB-R250) is the recommended staining agent.

5) The following PVDF membranes are recommended:

    KMD Bioscience is committed to providing clients with comprehensive protein analysis services, including protein N-terminal sequencing. Leveraging advanced mass spectrometry technology and our extensive experience, we can precisely determine the N-terminal sequence of proteins, delivering accurate and reliable experimental results to our clients. Whether clients need to sequence purified protein samples or analyze proteins in complex mixtures, we are able to meet their needs. Our professional team will provide you with fast, efficient, and precise services, ensuring you gain an in-depth understanding of protein structure and function. Choosing KMD Bioscience’s protein N-terminus sequencing service will provide vital support and assistance for your research.