What is the turnaround time for gel band analysis?

Our goal is to be able to provide preliminary data within one week. A gel band sample submitted on Monday will be ready the following Monday.

How pure does the sample need to be?

Any protein that can be cut from a gel can be sequenced, no matter how many additional bands are present in the gel. There will always be some concern that a band is composed of more than one protein, but this should not affect the ability to detect and sequence peptides produced in the digestion.

Can I identify post-translational modifications?

Post-translational modifications can be identified by mass spectrometry; however these experiments generally require more protein than the identification experiments. This is especially true for modifications that are sub-stoichiometric in nature. One of the inherent difficulties in these types of analysis is identifying a low abundant modified peptide present in a complex peptide mixture. Several different strategies can be used to increase the likelihood of success in these experiments including large amounts of protein, increasing the stoichiometry of the modification reactions, using targeted analysis and multiple proteases

Can the amounts of my protein or post-translational modification be quantified?

Relative quantities of proteins and post-translational modifications can be determined in these experiments. In order to achieve this, an internal standard must be utilized as a normalization factor. Fortunately, in most samples an unchanging tryptic peptide inherent in the sample can serve as an internal standard.