Blog Articles2020-06-18T16:21:28-04:00

Blog Articles

Distinguishing between Isoleucine and Leucine

Isoleucine (Ile, I) and leucine (Leu, L) are isobaric residues or amino acids with the same mass (Figure 1). Conventional mass spectrometry-based proteomics cannot be easily used to distinguish between Ile and Leu. In 2016, Rapid Novor became the first to commerc­­ially introduce a service, w-ion isoleucine-leucine determination (WILD® ), to distinguish between Ile and Leu in de novo antibody sequencing. Figure 1. Leucine (Leu, L), and isoleucine (Ile, I) amino acids’ chemical structure, molecular weight (Da) (mass which includes the extra H2O) and monoisotopic residue mass (Da) (does not include the hydroxyl group of the carboxylic acid nor [...]

January 7th, 2020|

How Mass Spectrometry Can Help Limit Reproducibility Problems

How much time is spent trying to find the right antibody? Photo Credit: María Rosales Gerpe Reproduced from Rosales Gerpe, M., Barber J., (Nov 8, 2019). How Mass Spectrometry Can Help Limit Reproducibility Problems. Scientific American, a Division of Springer Nature America, Inc., with permission.  Antibodies are critical for biological and medical research. Yet, since early 2015, the state of the antibody industry has been described as being in a reproducibility crisis. One of the main issues is the improper characterization of primary antibodies. The health research industry is saturated with discrepant validation data on the sensitivity, specificity [...]

November 13th, 2019|

Antibody Species Q&A

Q: What antibody species can you sequence? A: All of them! We are able to sequence any species because we use de novo protein sequencing by tandem mass spectrometry (MS/MS). This type of protein sequencing by mass spectrometry does not rely on existing databases that might introduce bias or wrong amino acid calls [1]. In addition, some species have yet to be sequenced and therefore do not have a genome or database to compare it to [1]. Our liquid chromatography MS/MS (LC-MS/MS) system coupled to our machine learning algorithms provide plenty of data to read each amino acid with sensitivity and [...]

August 26th, 2019|

Shipping Conditions Q&A

Q: Under what shipping conditions should I send my protein sample? A: We suggest the following shipping conditions: We recommend that you ship your samples either lyophilized or in solution. If your samples are already lyophilized it is best to ship them to us in that form, they can be shipped at ambient temperatures, and are suitable for transfers longer than 24h. In-solution samples should be shipped in cold conditions, with either multiple cold packs to last travel time or in dry ice. Keep in mind that dry ice will only last 18-24 hours. We are able to accommodate [...]

August 19th, 2019|

Protein Purity Q&A

Q: How much protein and what purity is needed for protein sequencing? A: We typically accept samples at 100 µg with at least 80% purity, rare in the field. To measure the amount of protein, you can use a microvolume spectrophotometer such as the Nanodrop or a traditional Bradford assay. To assess purity of your samples, you may first start by running your sample on a reducing SDS-PAGE acrylamide gel. If you would like to send an antibody, you should be able to see two distinct bands at 25 kDa and 50 kDa for the light and heavy chains, [...]

August 12th, 2019|

Protein Contaminants Q&A

Q: What are common contaminants that could affect my protein sequencing results? A: Typical contaminants that we see affecting samples are non-target proteins, and non-target antibodies [1, 2, 3]. Protein Contaminants The most common protein contaminants include keratin and serum albumin [1, 2, 3]. Other Mass Spectrometry (MS) protein contaminants identified in research labs worldwide by a recent Human Proteome Organization study are casein and E. coli proteins [3]. Keratin is an epidermal structural protein that is found on the outer layer of skin, hair, nails and eventually in dust [1, 3]. Keratin is especially difficult because its size ranges between [...]

August 5th, 2019|

What is Protein Sequencing by Mass Spectrometry?

Frederick Sanger, father of DNA sequencing, sequenced the first protein, insulin, before he began his efforts in deciphering nucleotide codes. Nowadays, DNA sequencing is so popular that it is easy to forget that the first sequenced biological material was protein – insulin, by Sanger [1, 2]. Sanger, and another researcher, Edman, separately pioneered protein sequencing. Edman degradation, also known as Edman sequencing, is still used, though it suffers from many shortcomings in contrast to today’s protein sequencing by Mass Spectrometry (MS). If you would like to learn more about Edman degradation and how it [...]

August 2nd, 2019|

Milestone: 1000 Projects

Meet Anthony: he likes having a quality meal. Balanced. With healthy fats like avocado. Anthony wakes up every morning to the smell of coffee and a strong sense of carpe diem. He doesn’t just employ the art of positive visualization, popularized by The Sopranos. His dogma, if a TV show’s principles could be dogma, is to embrace the spirit of competition and fully seize each day. He leads by example and walks tall, literally. Standing at 6’3”, he gazes ahead with clarity and tackles every challenge. Today, he marked a great milestone for our company, 1000 projects, unprecedented for a [...]

July 29th, 2019|

Highlights from ASMS 2019

This year’s American Society for Mass Spectrometry (ASMS) conference took place in Atlanta, Georgia, the peach state of the US. Our Proteomics Specialist, Kathleen Gorospe, brought back home some delicious peach cookies, for which we have no pictures because they were devoured instantly. The ASMS conference was very fruitful indeed. There was a total of 384 oral presentations, more than 2700 poster presentations, in addition to training courses, and nightly workshops on important topics for the Mass Spectrometry (MS) community. Kathleen (front row, middle) at the Bioinformatics of Protein Identification course at ASMS 2019. Kathleen attended one of [...]

July 17th, 2019|