September 2021

Structure of an Amino Acid

2021-10-12T12:56:46-04:00September 14th, 2021|Articles|

Amino acids are small organic molecules that make up peptides and proteins. All living organisms share the same set of amino acids. Amino acids come together in different orders (sequences) to form proteins. As such, each type of protein has a different three-dimensional structure and biological activity.

Why is Protein Sequencing Useful

2021-10-12T13:01:28-04:00September 3rd, 2021|Articles|

Protein sequencing is a method that typically utilizes mass spectrometry (MS) to determine the amino acid code of a protein1. Prior to the development of mass spectrometry, Edman degradation, a method involving the stepwise degradation of peptides to derive the order of amino acids, was the mainstream approach. Nowadays, mass spectrometry is favored due to its ease of use and high throughput capabilities, though Edman degradation is still employed for specific applications in which the technique is well suited.

August 2021

What are Monoclonal Antibodies?

2021-10-12T13:04:45-04:00August 25th, 2021|Articles|

Monoclonal antibodies (mAbs) are homogenous antibodies that bind to a single epitope on an antigen. Kohler and Milstein generated the first mAbs when they developed hybridoma technology in the 1970s. Because of the specificity, homogeneity and unlimited availability, mAbs are valuable reagents used in a variety of important applications including treatment and diagnosis of diseases

How to Determine Peptide Sequences

2021-10-12T13:07:21-04:00August 17th, 2021|Articles|

Amino acids (aa)—the building blocks of proteins—are simple molecules characterized by a variable R group flanked either side by an amino group and a carboxyl group. With around 20 different commonly found amino acids, each one can bond with another to produce chains that can be classified as peptides (typically below 50 aa) and proteins (sequences above 50 aa)—molecules ubiquitous to every known organism.

Key Pain Points in Amino Acid Sequencing & How to Avoid Them

2021-10-12T13:12:09-04:00August 13th, 2021|Articles|

Amino acid sequencing is commonly performed using Edman degradation or mass spectrometry (MS). While mass spectrometry is favoured for its high throughput capabilities and ease of use, both techniques possess their own features and limitations. This article summarizes some of the key pain points inherent in the two methodologies when determining the amino acid sequence.

De Novo Protein Sequencing Vs. DNA Sequencing

2021-10-04T15:06:25-04:00August 1st, 2021|Articles|

Written by Yuning Wang, PhD August 1, 2021 What is DNA Sequencing? DNA sequencing is the process of determining the precise order of four nucleotides bases—adenine (A), guanine (G), cytosine (C), and thymine (T)—that make up the DNA molecule. From Sanger sequencing to next-generation sequencing (NGS), DNA sequencing’s accessibility and ease [...]

July 2021

Why Verifying the Protein Sequence Is Crucial for Antibody Validation

2021-10-04T15:29:50-04:00July 23rd, 2021|Articles|

Written by María Gerpe, PhD July 23, 2021 Why the Amino Acid Sequence Matters As proteins are assembled, they fold into different structural orders: from primary to quaternary. The exact sequence of the primary structure (the amino acid sequence) will dictate how a protein will fold and therefore function. The importance [...]

What is the De Novo Amino Acid Sequencing Method?

2021-10-12T13:17:31-04:00July 19th, 2021|Articles|

Proteins are composed of peptide chains, which in turn are made up of a string or linear sequence of amino acids (Figure 1A). Every amino acid has a basic structure containing an amino (-NH2) group and a carboxylic (-COOH) group (Figure 1B). To form a peptide, amino acids link to each other via a peptide bond, which involves the reaction between the carboxylic group of one amino acid and the amine group of another amino acid (Figure 1B). As such, the primary structure of a protein is typically recorded starting at the amino-terminal (N) end and continuing to the carboxyl-terminal (C) end. The primary protein structure may be directly sequenced from a sample of the protein itself or inferred from the DNA sequence.

What is Protein Mass Spectrometry?

2021-10-12T13:18:59-04:00July 18th, 2021|Articles|

Protein mass spectrometry refers to the use of mass spectrometry in the study and characterization of proteins, including their quantification, profiling, interaction mapping, and identification of their post-translational modifications (1,2). Protein mass spectrometry may also be referred to as mass spectrometry-based proteomics. Mass spectrometry-based proteomics consist of three approaches: top-down, middle-down, and bottom-up proteomics

How do You Obtain the Sequence of an Antibody?

2021-10-12T13:22:03-04:00July 10th, 2021|Articles|

Antibody sequences are critical for antibody engineering and protein characterization in therapeutic development. For antibody reagent users, knowing the sequences allows them to perform sequence analysis/alignment to identify binding and cross-reactivity so they can conduct rational experiment design.

Isoleucine and Leucine

2021-10-12T13:24:34-04:00July 7th, 2021|Articles|

Because they share the same mass, isoleucine and leucine are known as isobaric amino acids. Conventional mass spectrometry-based proteomics cannot be easily used to distinguish between isoleucine and leucine.

What is Amino Acid Sequencing?

2021-10-12T13:26:10-04:00July 5th, 2021|Articles|

Amino acid sequencing is the process of identifying the arrangement of amino acids in proteins and peptides. Numerous distinct amino acids have been discovered in nature but all proteins in the human body are comprised of just twenty different types.

June 2021

Types of Antibodies

2021-10-05T08:42:43-04:00June 25th, 2021|Articles|

Written by María Gerpe, PhD June 25, 2021 Introduction Antibodies or immunoglobulins (Ig) are Y-shaped glycoproteins produced by the adaptive immune system in response to antigens - substances or molecules the immune system deems as foreign. Antibodies bind to an antigen and either directly neutralize it, or activate other parts of [...]

August 2019

Protein Sequencing & Antibody Species

2021-10-15T09:20:25-04:00August 26th, 2019|Articles|

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.

Protein Sequencing and Protein Purity

2021-10-15T09:25:40-04:00August 12th, 2019|Articles|

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.

Protein Sequencing and Contaminants

2021-10-15T09:28:16-04:00August 5th, 2019|Articles|

The most common protein contaminants include keratin and serum albumin. Other Mass Spectrometry (MS) protein contaminants identified in research labs worldwide by a recent Human Proteome Organization study are casein and E. coli proteins.

February 2017

Antibody Protein Sequence Analysis Using Mass Spectrometry

2021-10-15T09:32:00-04:00February 3rd, 2017|Articles|

One of the most important pieces of information researchers need to know during early stage antibody drug research and development is the sequence information of the antibody protein. With the advancement of mass spectrometry instrumentation and technologies, it is helpful, and sometimes critical, to conduct sequence analysis using mass spectrometry experiments.

June 2016

Moving Towards Recombinant Monoclonal Antibodies

2021-10-15T09:36:33-04:00June 30th, 2016|Articles|

Recombinant Monoclonal Antibodies (rAbs) are highly reproducible, customizable and pure alternatives to the traditional antibodies produced by hybridomas. Get the antibody protein sequence, either by DNA sequencing or the de novo protein sequencing technology, you can rest assured that you can have the exact antibody made recombinantly anytime in the future.