Written by María Gerpe, PhD Contents What are recombinant antibodies? What is the difference between recombinant and traditional antibodies? Why are recombinant antibodies important? Types of recombinant antibodies How are recombinant sequences obtained? Additional Resources References What are recombinant antibodies? Recombinant antibodies are [...]
Written by Yuning Wang, PhD What is protein purity? When scientists refer to protein purity, they are referring to a sample's properties and homogeneity. Ideally, if a sample contains protein B, the sample should only contain protein B, rather than protein B and x, y, z proteins and non-protein molecules. Furthermore, the homogeneity [...]
Written by Yuning Wang, PhD, and María Gerpe, PhD IgBLAST Definition Developed by the National Center for Biotechnology Information (NCBI), IgBlast is a tool for the analysis of immunoglobulin and T cell receptor sequences in FASTA format. Using Basic Local Alignment Search Tool (BLAST) technology, IgBlast identifies similar sites within nucleotide or [...]
Peptide mapping is a widely used analytical technique to verify the primary structure (amino acid sequence) and characterize the chemical modifications of a protein. It analyzes peptides generated from the digestion of an isolated protein, or a protein mixture
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.
The transition from polyclonal antibody drugs to a more targeted monoclonal approach was made possible through a series of scientific and technological advancements; the most notable of which is the hybridoma technique developed by Köhler and Milstein, which allowed the generation of pure antibodies at scale.
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.
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
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.
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.
Antibodies are used in a variety of ways in academia and industry, from tools to therapeutics. Because antibodies are produced using live processes, which are naturally error-prone, validation is required from time to time. Furthermore, to develop biological therapeutics, the protein sequence must be confirmed as part of the regulatory process.
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 [...]
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 [...]
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.
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
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.
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.
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.
Bispecific therapeutics are monoclonal antibodies that carry a specific antigen-binding capability on each arm. Bispecifics are thus capable of having two specificities that can either double the binding affinity of the antibody toward the same antigen (increased avidity), or can now bind to two targets. Bispecifics are most often described as two types: trispecifics and bispecific T-cell engaged antibodies (BiTE).
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 [...]
Written by María Gerpe, PhD June 18, 2021 Introduction Research publications represent an additional source of validation proof for commercially available antibodies. As such, academic and industry scientists often also rely on publication references to decide which commercial antibody to purchase. Several independent efforts exist to compile such information. For instance, [...]
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.
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.
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.
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.
Nowadays, DNA sequencing is so popular that it is easy to forget that the first sequenced biological material was protein – insulin, by Sanger. Sanger, and another researcher, Edman, separately pioneered protein sequencing.
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.
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.