Frequently Asked Questions

Q. What chemicals interfere with protein sequence analysis?

A. To avoid problems with Edman chemistry, the samples should be free of the following reagents:

1. Buffers and primary amines: Tris buffer is commonly used for protein purification. Tris and glycine are common in samples recovered from SDS-PAGE.

2. Glycerol and sucrose: These reagents are often added to buffers designed for the storage and handling of proteins. These compounds are not volatile and leave a highly viscous residue.

3. Nonionic detergents: Triton X-100, Brij, and Tween solutions often contain aldehydes, oxidants and other contaminates that can inhibit Edman degradation.

4. SDS: Large quantities of SDS can cause instrument malfunction and may lead to the loss of sample from the filter.

Dialysis tubing is often a source of contaminants and other interfering substances. Avoid dialysis as a last step in sample preparation or use thoroughly cleaned, high-quality tubing. Always dialyzed against a salt counterion or dilute acid to prevent the protein and contaminates that may be present from sticking to the tubing.

Q. What are your turnaround times?

A. Turnaround times depend on the work in progress, but here are some estimated times:

Protein Sequencing: 2 days
Protein Synthesis: 1-2 weeks per peptide
Amino Acid Analysis: 2 days
HPLC analysis: 1-2 days