Supplier: SCIEX

The Sciex Triple Quad 4500 System is a high sensitivity, bench top triple quadrupole mass spectrometer designed for LC-MS/MS analyses. This instrument provides excellent robustness and long term stability for the most demanding assays.

Supplier: Biosensis

GDNF is a glycosylated, disulfide-bonded homodimer molecule. It was first discovered as a potent survival factor for midbrain dopaminergic neurons and was then shown to rescue these neurons in animal models of Parkinson's disease. GDNF is about 100 times more efficient survival factor for spinal motor neurons than the neurotrophins. FUNCTION: Neurotrophic factor that enhances survival and morphological differentiation of dopaminergic neurons and increases their high-affinity dopamine uptake. SUBUNIT: Homodimer; disulfide-linked. SUBCELLULAR LOCATION: Secreted protein. ALTERNATIVE PRODUCTS: 2 named isoforms produced by alternative splicing. DISEASE: Defects in GDNF may be a cause of Hirschsprung disease (HSCR). In association with mutations of RET gene, defects in GDNF may be involved in Hirschsprung disease. This genetic disorder of neural crest development is characterized by the absence of intramural ganglion cells in the hindgut, often resulting in intestinal obstruction. DISEASE: Defects in GDNF are a cause of congenital central hypoventilation syndrome (CCHS); also known as congenital failure of autonomic control or Ondine curse. CCHS is a rare disorder characterized by abnormal control of respiration in the absence of neuromuscular or lung disease, or an identifiable brain stem lesion. A deficiency in autonomic control of respiration results in inadequate or negligible ventilatory and arousal responses to hypercapnia and hypoxemia. SIMILARITY: Belongs to the TGF-beta family. GDNF subfamily.

Supplier: Invitrogen

Thermo Scientific Pierce SMCC is a hetero-bifunctional crosslinker that contain N-hydroxysuccinimide (NHS) ester and maleimide groups that allow covalent conjugation of amine- and sulfhydryl-containing molecules. NHS esters react with primary amines at pH 7–9 to form amide bonds, while maleimides react with sulfhydryl groups at pH 6.5–7.5 to form stable thioether bonds. In aqueous solutions, NHS ester hydrolytic degradation is a competing reaction whose rate increases with pH. The maleimide group is more stable than the NHS-ester group, but will slowly hydrolyze and lose its reaction specificity for sulfhydryls at pH values > 7.5. For these reasons, conjugations with these crosslinkers are usually performed at pH 7.2–7.5, with the NHS ester (amine-targeted) reacted before or simultaneous with the maleimide (sulfhydryl-targeted) reaction.

Supplier: Invitrogen

Thermo Scientific Pierce DSP (Lomant's Reagent) is a water-insoluble, homo-bifunctional N-hydroxysuccimide ester (NHS ester) crosslinker that is thiol-cleavable, primary amine-reactive, and useful for many applications. DSP contains an amine-reactive NHS ester at each end of an 8-carbon spacer arm. NHS esters react with primary amines at pH 7–9 to form stable amide bonds and releasing N-hydroxy-succinimide. Proteins, including antibodies, generally have several primary amines in the side chain of lysine (K) residues and the N-terminus of each polypeptide that are available as targets for NHS ester crosslinking reagents. DSP is non-sulfonated and insoluble in water, so it must first be dissolved in an organic solvent and then added to the aqueous reaction mixture. Because DSP does not possess a charged group, it is lipophilic and membrane-permeable and so useful for intracellular and intramembrane conjugation. A sulfonated analog of DSP (DTTSP) is water soluble. DSS, the non-cleavable analog of the DSP crosslinker is also available for applications that require a stable spacer arm that cannot be cleaved in the presence of reducing agents.

Supplier: Biosensis

The spectrin family of proteins were originally discovered as major components of the submembraneous cytoskeleton of osmotically lysed red blood cells (1). The lysed blood cells could be seen as clear red blood cell shaped objects in the light microscope and were referred to as red cell "ghosts". The major proteins of these ghosts proved to be actin, ankyrin, band 4.1 and several other proteins, including two major bands running at about 240kDa and 260kDa on SDS-PAGE gels. This pair of bands was named "spectrin" since they were discovered in these red blood cell ghosts (1). Later work showed that similar high molecular bands were seen in membrane preparations from other eukaryotic cell types. Work by Levine and Willard described a pair of about ~240-260kDa molecular weight bands which were transported at the slowest rate along mammalian axons (2). They named these proteins "fodrin" as antibody studies showed that they were localized in the sheath under the axonal membrane, but not in the core of the axon (2; fodros is Greek for sheath). Subsequently fodrin was found to be a member of the spectrin family of proteins, and the spectrin nomenclature is now normally used (3). Spectrins form tetramers of two alpha and two beta subunits, with the alpha corresponding to the lower molecular weight ~240kDa band and the beta corresponding to the ~260kDa or in some case much larger band. The alpha-II subunit is widely expressed in tissues but, in the nervous system, is found predominantly in neurons. The antibody can therefore be used to identify neurons and fragments derived from neuronal membranes in cells in tissue culture and in sectioned material.

Supplier: Invitrogen

Thermo Scientific Pierce DSP (Lomant's Reagent) is a water-insoluble, homo-bifunctional N-hydroxysuccimide ester (NHS ester) crosslinker that is thiol-cleavable, primary amine-reactive, and useful for many applications. DSP contains an amine-reactive NHS ester at each end of an 8-carbon spacer arm. NHS esters react with primary amines at pH 7–9 to form stable amide bonds and releasing N-hydroxy-succinimide. Proteins, including antibodies, generally have several primary amines in the side chain of lysine (K) residues and the N-terminus of each polypeptide that are available as targets for NHS ester crosslinking reagents. DSP is non-sulfonated and insoluble in water, so it must first be dissolved in an organic solvent and then added to the aqueous reaction mixture. Because DSP does not possess a charged group, it is lipophilic and membrane-permeable and so useful for intracellular and intramembrane conjugation. A sulfonated analog of DSP (DTTSP) is water soluble. DSS, the non-cleavable analog of the DSP crosslinker is also available for applications that require a stable spacer arm that cannot be cleaved in the presence of reducing agents.