Posts Tagged ‘Antibody database’

« Older Entries

Working with the V5 Tag Antibody

Friday, June 10th, 2011

The V5 tag antibody identifies the V5 epitope tag, enabling proteins of interest to be analysed and studied via ELISA, Western blot and other immunochemical methods. We at Novus Biologicals are one of the leading suppliers of epitope tag reagents, with an extensive range of V5 tag antibody products on our antibody database.

An epitope tag is a short peptide sequence, which is bioengineered onto the N- or C- terminus of a protein so it can be recognised by the equivalent antibody, or antibody paratope (i.e. the area of the immunoglobulin receptive to that tag).

Epitope tags are created using recombinant DNA technology, which allows the fusion of a short sequence of foreign peptides (such as from a virus) with the target gene’s DNA. When this protein is introduced into cells, the protein is expressed in its tagged form. The V5 tag antibody acts as a universal reagent for any recombinant protein carrying the V5 tag, thus avoiding the need to generate individual antibodies for specific proteins. V5 epitope tags are useful as their small size does not interfere with the biochemical properties of the proteins being studied.

The V5 epitope tag represents the amino acid residues 95-108, gly lys pro ile pro asn pro leu leu gly leu asp thr (GKPIPNPLLGLDST), of the RNA polymerase alpha subunit of the SV5 (simian virus 5) paramyxovirus. We have a number of conjugated and non-conjugated V5 tag antibody products on our antibody database. Our SV5-Pk V5 tag antibody products are specific to the small Pk epitope of the P and V proteins of the SV5 virus, and are used to identify membrane-bound and secreted proteins.

Tags: ,
Posted in Antibodies | No Comments »

The Ki67 Antibody in Cell Marker Studies

Monday, May 30th, 2011

The MK167, or Ki67 antibody recognizes a nuclear protein encoded by the MK167 gene. Ki167 is involved with RNA transcription and essential to cellular proliferation, being expressed by proliferating cells at all stages of the active cell cycle; it is exclusively used as a marker for cellular proliferation. The Ki67 antibody is a useful tool in cancer research and neuronal studies; however, MIB-1 antibodies also target the Ki67 marker and are preferred for clinical use.

During interphase, Ki67 is exclusively located in the nucleus, but relocates to the chromosome surface during cell division. The Ki67 antibody is a highly useful aid for determining the growth faction of cell populations in neoplasms and tumours, particularly those of the brain, prostate and breast. The faction of Ki67-positive tumour cells is called the Ki-67 labelling index, the value of which strongly correlates to the clinical development of cancer. Low Ki67 indices are indicative of low-grade tumours and a more favourable outcome for the patient.

For determining the Ki67 index in clinical applications, the Ki67 antibody has largely been superseded by MIB1 antibodies. This is because they were found to target the Ki67 antigen in the same way, but with the added advantage of being viable for use in paraffin-embedded immunohistochemistry assays, following microwave-mediated antigen retrieval. This situation has improved, and today around half the Ki67 antibodies we at Novus Biologicals have in our antibody catalog can be used for paraffin embedded sections. However, these products are exclusively for research use only, and MIB1 antibodies remain the norm in the clinical environment.

Tags: , , ,
Posted in Antibodies | No Comments »

The Osteopontin Antibody and Hepatic Research

Monday, May 23rd, 2011

Antibody suppliers, such as us at Novus Biologicals, supply a wide range of cell marker products, among them the osteopontin antibody. Recently, the osteopontin antibody has proven useful in hepatic cancer research.

Osteopontin (OPN) is mainly expressed by the osteoblasts; its primary function is in the mineralization of bone. However, OPN is expressed to a lower degree in other areas of the body, being involved in cell adhesion, cell migration and the inflammatory response.

Osteopontin has been implicated in a number of inflammatory diseases including rheumatoid arthritis (RA), multiple sclerosis and hepatitis. It is also upregulated in a number of cancers. Osteopontin antibody studies have shown OPN is modified in a number of tissue-specific ways, including phosphorylation, glycosylation, sulphation and transglutamination.

OPN is known to have two central domains with multiple integrin binding sites, which are activated following thrombin-induced cleavage. Cleavage can also be initiated by MMP proteins at central and C-terminal sites, although C-terminal binding seems to have no integrin effect. Importantly, OPN can undergo complete digestion by MMP-9, resulting in the release of a 5 kDa fragment. In 2007, Takafuji et al published a study showing this fragment to play a role in the development of hepatocellular carcinomas, promoting CD44-mediated metastasis.

Administration of neutralizing murine osteopontin antibody has proven successful in treating RA and fulminant hepatitis in mice, but is of little clinical use in humans. Recently, B. Zhang et al succeeded in ‘humanising’ a murine osteopontin antibody, while retaining full binding affinity. The study strongly suggested humanized anti-osteopontin antibody may have a therapeutic use in humans, though it must be stressed the products sold by antibody suppliers are for research use only.

Tags: , , ,
Posted in Antibodies | No Comments »

Signalling Advances in Adiponectin Antibody Research

Monday, May 16th, 2011

Adiponectin is an adipocytokine protein that positively regulates metabolism of lipids and glucose by suppressing glucose production from the liver, stimulating insulin sensitivity, and increasing the rate of fatty acid oxidation and glucose uptake. Insulin resistance, obesity and dyslipidemia (abnormal blood lipid levels) are all linked to Adiponectin deficiency. The Adiponectin antibody is also used in Type 2 Diabetes research.

In recent years, a number of antibody studies have focussed on the metabolic pathways governing Adiponectin. In 2003, Yamauchi et al identified two Adiponectin receptors, Adipo R1 and Adipo R2. Subsequent experiments showed Adipo R1 to be the primary receptor in skeletal muscle, which is the body’s main glucose-utilising tissue. However, the underlying mechanism of action remained unclear.

In 2010, M. Iwabu et al published a paper which significantly advanced Adiponectin antibody research, disclosing new facts about the Adipo R1 signalling pathway. Using mice depleted of skeletal muscle Adipo R1- (m-Adipo R1KO), the researchers were able to confirm Adipo R1 affected insulin sensitivity and glucose tolerance. Markedly higher insulin and plasma glucose levels were recorded in m-Adipo R1KO mice than wild-type controls, while antibody assays also revealed marked alterations in insulin-induced phosphorylation of key signalling molecules, including Akt, IRS-1, JNK and p70 S6 kinase. The m-Adipo R1KO group also showed decreased mitochondrial biogenesis, with reduced levels of mitochondrial proteins, PGC1 alpha transcription factor and mitochondrial DNA.

The m-Adipo R1KO mice also demonstrated enhanced oxidative stress coupled with impaired oxidation of fatty acids, a common occurrence with insulin resistance. These effects were partially reversed by exercise, showing exercise may be a useful therapeutic tool in cases of impaired Adiponectin function. We at Novus Biologicals have a wide range of Adiponectin antibody products in stock.

Tags: , , ,
Posted in Antibodies | No Comments »

Actin Nucleators and Other Developments in Actin Antibody Research

Friday, May 13th, 2011

A highly conserved, abundant protein found in practically all eukaryotic cells, actin is a monomeric subunit of skeletal muscle thin filaments, and cytoskeleton microfilaments. Actin antibody products are routinely used in cell marker and loading control assays. However, actin antibody reagents are also used for cytoskeleton, cell motility, cytokinesis and cell signalling research. Our antibody catalog covers all the actin isoforms, with an extensive range of alpha, beta and gamma actin antibody products.

Actin antibody studies have revealed polymerization and depolymerization of actin to be essential to chemotaxis (cell motility) and cytokinesis (cell division). Polymerization is dependent upon nucleating factors such as ARP and the formin protein family. The Arp1/2 complex has been widely studied by actin antibody researchers. The Arp1 and 2 proteins mimic the structure of monomeric actin, forming a complex which serves as a nucleation site for new microfilaments. The formins are, like actin, highly conserved proteins involved in actin remodelling, cellular morphology and coordination of microtubule and actin dynamics.

Recent actin antibody research has identified several cellular factors which modulate formin expression to affect actin nucleation and elongation. Formins with cellular functions apart from actin polymerization have also been discovered. Recent additions to the formin nucleator database include Cordon-Bleu, Cappuccino, Leiomodin and Spire. In addition, several proteins have been identified which stimulate ARP2/3 activity to affect actin nucleation and dynamics. These include WASH (the WASP and SCAR homologue); WHAMM (WASP homologue associated with actin, membranes and microtubules) and the junction-mediating regulatory protein JMY.

Actin antibody research continues to uncover new genetic facts about actin polymerization and the cytoskeleton. We at Novus Biologicals have an extensive antibody catalogue covering this area of research.

Tags: , , ,
Posted in Antibodies | No Comments »

The Akt Antibody and its Role in Cancer Research

Monday, May 9th, 2011

There are three human isoforms of the AKT gene, which plays a key role in several signalling pathways. Akt antibody studies have shown the Atk kinases to play a diverse number of roles within the cell, regulating angiogenesis, apoptosis, protein synthesis, intermediary metabolism and cellular differentiation. We at Novus Biologicals have a wide range of Akt products on our antibody database, targeting all three isoforms.

Akt antibody research has identified specific roles for the three isoforms of Akt. Akt2 plays an important role in insulin signalling, while Akt3 is thought to be involved with neuronal development. Akt1, the founding member of the family, is of major importance to cancer researchers. A key player in the PI3K/AKT/mTOR and several other pathways, Akt1 signalling promotes hypertrophy (growth) of skeletal muscle and other tissues, and promotes cell survival by inhibiting apoptotic processes.

Akt1 was originally identified as an oncogene in the AKT8 transforming retrovirus, and has since been shown to be critical to the growth and progression of a number of human neoplasms. It also plays an indirect role, acting on oncogenic signals resulting from mutations in tumour-suppressor genes and other oncogenes.

Today, the entire Akt antibody database is used in cancer research. Overexpression of Akt2 and Akt3 has been directly linked to the development of epithelial neoplasms, breast tumours, prostate cancer, ovarian cancer and skin cell melanomas. Researchers at the MORI Institute, Tufts University, are using insertional mutagenesis and other genetic techniques to probe the function of all three isoforms. Other groups are using Akt antibody products to develop antineoplastic drugs.

Tags: , , ,
Posted in Antibodies | No Comments »

Research Using the 160kDa Medium Neurofilament Antibody

Friday, April 29th, 2011

Neurofilaments (NFs) are intermediate filaments found almost exclusively in neuronal cells, and play an essential role supporting the cytoskeleton. In vertebrates they are composed of three intertwining polypeptide subunits of varying length and molecular weight – the light, medium and heavy NF chains. We at Novus Biologicals have an extensive range of neurofilament antibody products on our antibody database.

The three NF chains share similar structures and base sequences, but vary in length and sequence at both the N and C-termini. In NF-H and NF-M subunits, the C-termini form extensions which link neurofilaments both to each other and to other cytoplasmic proteins.

Neurofilament antibody research advanced a long way with the advent of SDS-PAGE (Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis), which enables proteins to be separated and accurately measured according to their electrophoretic mobility. NF-L, M and H subunits are 68-70kDa, 145-160 kDa and 200-220kDa in size respectively, with protein sizes varying according to species.

Neurofilament antibody products are widely used in neuropathology immunostaining assays, as overexpression of neurofilaments is a feature of many diseases. They are routinely used in NF cell marker studies.

In 2002, Duplan et al used 160kDa neurofilament antibody assays to study antitumor FGF (fibroblast growth factor) activity relative to FGF receptor expression in medulloblastoma tumor variants. More recently the 160kDa neurofilament antibody has been used in a study linking human TDP-43 expression in mouse motor neurons to growth deformities and early death. The NF products on our antibody database are suitable for use in a wide range of assays including western blot, immunocytochemistry, immunohistochemistry and immunoprecipitation.

Tags: , ,
Posted in Uncategorized | No Comments »

Using the Laminin Antibody in Angiogenesis Research

Monday, April 11th, 2011

Laminin is one of a large number of proteins expressed on the basal laminar of the ECM (extracellular matrix). The laminin antibody database covers several proteins, which interact with integrins and other receptor proteins to support cellular differentiation, morphology, migration, cell survival and the maintenance of tissue phenotypes. Laminin antibody studies have played a key role in research into angiogenesis and tumour development.

The ECM plays an essential role in angiogenesis, providing support for the developing blood vessel and releasing pro- and anti-angiogenic factors which regulate stability and cell survival. During angiogenesis, the ECM basal membrane is degraded, enabling migration of endothelial cells. Although angiogenesis is necessary for wound healing, it is also a feature of metastasis and tumour formation.

The laminins are a family of around 15 trimeric alpha/beta/gamma-chain proteins. Laminin I has been identified as a major promoter of angiogenesis, with endothelial cells shown to differentiate into capillary-like structures on a laminin I-enriched Matrigel matrix. Recent laminin antibody research has identified laminin I to have 20 angiogenic sites, with the α5ß1 and αvß3 integrins identified as surface receptors. These have been shown to specifically target the C16 Y1 chain peptide, which is the only Y1 chain to block laminin I adhesion to collagen and fibronectin. C16 has been shown to be angiogenic in vivo.

We at Novus Biologicals have an extensive antibody database covering laminin research. Among our products is a mouse laminin antibody kit suitable for sandwich ELISA assays. It contains 96-well strips pre-coated with a capture polyclonal mouse laminin antibody; biotinylated polyclonal laminin antibody; an enzyme Avidin-Biotin-Peroxidase complex and a peroxidase substrate. This kit allows convenient and accurate analysis of laminin concentrations in sera, plasma, lysates and supernates.

Tags: , ,
Posted in Angiogenesis | No Comments »

The GAPDH Antibody – a Diverse Area of Research

Monday, March 21st, 2011

The glyceraldehyde 3-phosphate dehydrogenase, or GAPDH enzyme plays an important role in the conversion of glucose for energy, catalyzing the sixth step of the glycolytic pathway. A common and widely expressed protein, GAPDH mRNA is often used as a standard in mRNA studies. GAPDH antibody products are also used as a loading control in Western blot assays. We at Novus Biologicals have 55 GAPDH antibody products on our antibody database.

GAPDH catalyses the reversible oxidative phosphorylation of glyceraldehyde 3-phosphate, yielding D-glycerate 1, 3-bisphosphate in a two-step process which couples phosphorylation to oxidation. Recent GAPDH antibody studies have suggested GAPDH also has a role to play in several non-metabolic processes, including transcription activation, ER to Golgi vessel shuttling and apoptosis. GAPDH is known to bind to a number of other proteins, including the amyloid precursor protein, mutations of which can cause Alzheimer’s disease.

In 2003, Zheng et al identified a transcriptional role for GAPDH, forming part of the OCA-S Oct-1 coactivator complex in combination with lactate dehydrogenase. It this study, GAPDH directly bound to Oct-1, and selectively bound to the H2B promoter during the S-phase. Other GAPDH antibody studies have suggested GAPDH plays a role in basal RNA polymerase II transcription, and also DNA repair.

In 2005, Hara et al showed that GAPDH initiates apoptosis in response to cellular stress, binding to the E3-ubiquitin ligase Siah1 following S-nitrosylation. In 2006, the same group showed that Deprenyl, a drug used to treat Parkinson’s disease, blocked S-nitrosylation of GAPDH, preventing Siah1 binding.

Neurodegeneration and apoptosis are closely intertwined. The GAPDH antibody database may turn out to be a useful tool in the fight against neurodegenerative disorders such as Alzheimer’s, Huntington’s and Parkinson’s disease.

Tags: , ,
Posted in Antibody database | No Comments »

HA-tag Antibody

Monday, March 14th, 2011

We at Novus Biologicals are one of the leading antibody suppliers of high affinity human epitope tag reagents, such as the HA tag antibody. Widely used in Western blot, ELISA and Immunohistochemistry assays, they offer a useful and reliable method for detecting, analyzing and purifying proteins from a wide range of species.

Short, immunoreactive epitope tags are highly useful reagents. They are small, so unlikely to interfere with the protein under test, but have a high degree of immunoreactivity, due to the fact they are generally derived from viral genes. The HA tag, for example, is derived from amino acids 98-106 of the human influenza haemagglutinin (HA) protein, an antigenic glycoprotein found on the surface of the human influenza virus.

Developed around 20 years ago, the HA tag can be expressed from a wide range of engineered recombinant proteins, and is widely used as a general epitope tag for expression vectors. The HA tag antibody recognizes overexpressed HA-tagged proteins in a wide range of cells, including transfected mammalian cells. For easy immunochemical analysis and visualization, it is usually engineered onto the N (amino) or C (carboxy) terminus of the protein being studied.

The HA tag antibody has proven invaluable in human disease research, being extensively used in both biochemistry and cell biology to track and isolate proteins, and precipitate them with other proteins in the pathway. They have proven invaluable in the complex field of apoptosis. However, in 2007 H. Zhang et al reported HA tag cleavage and loss of immunoreactivity during apoptosis. Luckily, antibody suppliers like us have plenty of alternatives, such as c-Myc and V-5 epitope tags.

Tags: , ,
Posted in Antibody suppliers | No Comments »

« Older Entries