Technical Support Articles

Why should I include a stage tip step in my PTMScan® experiment?

For PTMScan experiments, the stage tip, or small-scale peptide desalting is a critical part of the experiment for a number of reasons. Detailed instructions for performing stage ti...

Why is the PTMScan® LysC Protease #84748 digestion performed at room temperature and not at 37°C?

The digestion is performed at room temperature to minimize carbamylation (also known as carbamoylation) of the sample peptides in the urea buffer, which can interfere with downstre...

Can I quantify my samples using the Senescence β-Galactosidase Staining Kit #9860?

The Senescence β-Galactosidase Staining Kit #9860 is intended to be a qualitative assay to determine if cells are senescent. We have not determined a means of quantification in-hou...

Have you done any cross-reactivity testing with α-CGRP, β-CGRP and unprocessed precursors using the CGRP (D5R8F) Rabbit mAb #14959?

Our CGRP (D5R8F) Rabbit mAb #14959 is produced with a synthetic peptide corresponding to residues surrounding Val114 of human CGRP protein (UniProt ID P06881 isoform 3; http://www....

Is prewashing the Protein A Magnetic Beads #73778 and Protein G Magnetic Beads #70024 necessary for my IP experiment?

We recommend washing the Protein A and Protein G magnetic beads prior to use to help clear them of any potential increase in background due to the buffer in which they are provided...

Why does c-Jun migrate at a higher molecular weight after treatment?

The transcriptional activity of c-Jun is regulated by SAPK/JNK phosphorylation at Ser63 and Ser73. The signaling pathway can be found at https://www.cellsignal.com/contents/science...

Can the Phospho-β-Catenin (Ser33/37) Antibody #2009 bind if the sites are singly phosphorylated or is the phosphorylation at both sites necessary?

We have tested the reactivity of the Phospho-β-Catenin (Ser33/37) Antibody #2009 to Ser33/37 by peptide dot blot. This antibody showed strong signal when phosphorylated at Ser37 al...

Do you have mouse-reactive antibodies available for SignalStar™ Multiplex IHC?

Are the Protein A Magnetic Beads #73778 and the Protein G Magnetic Beads #70024 hydrophilic or hydrophobic?

The base particle of the Protein A Magnetic Beads #73778 and the Protein G Magnetic Beads #70024 is somewhat hydrophilic. It is difficult to predict the hydrophilicity or hydrophob...

My items say to store at -20°c but they were shipped in an envelope. Is it ok to use?

Yes, it is safe to use these items. Since 2003, CST has been shipping antibodies at room temperature when possible to reduce waste from packing materials. All CST antibodies are st...

What is the best way to choose an antibody for my CUT&RUN assay if I cannot find a CUT&RUN validated antibody for my target protein?

When selecting an antibody for use in CUT&RUN, we recommend starting with a ChIP or ChIP-seq-validated antibody; however, we have found that not all ChIP-validated antibodie...

I don’t see my target of interest in your menu of available antibodies for SignalStar™ Multiplex IHC. Can I still use it in my panel in some way?

SignalStar Multiplex IHC kits and reagents haven’t yet been validated for use with antibodies outside of our menu. We’re in the proces...

What is the difference between phospho-Smad2 (Ser465/467) and phospho-Smad2 (Ser245/250/255)?

Phosphorylation of serines 465 and 467 indicates Smad2 activation and nuclear localization; whereas, phosphorylation of serines 245, 250, and 255 is inhibitory and leads to retenti...

Why do I see a doublet when using my total Histone H3 antibody for western blot?

We see this doublet phenomenon often in a number of different cell lines that we test with our Histone H3 antibodies. It does appear to be sample dependent. The doublet may be due ...

Which nuclear dyes can be used for In-Cell Western assays in combination with DyLight 680-conjugated secondary antibodies?

When performing In-Cell Western assays with DyLight 680-conjugated secondary antibodies, we recommend using either Hoechst 33342 or DAPI as a nuclear dye. DRAQ5 cannot be used beca...

How many LC-MS/MS injections are obtained from a PTMScan® enrichment?

Each PTMScan® enrichment contains sufficient peptides for three to four LC-MS/MS runs. Therefore, one enrichment can produce enough peptides for technical replicates and enough rem...

Why does the PINK1 (D8G3) Rabbit mAb #6946 detect two bands for human PINK1?

In endogenous samples, the PINK1 precursor protein (~60kDa), is imported into mitochondria where it is processed into a cleaved form (~50kDa) that is transported back to the cytopl...

What is an appropriate positive control to include in this SignalStar™ assay? Are multiple controls necessary?

Any tissue shown to be positive for each marker via chromogenic IHC can serve as a positive control tissue for a SignalStar™ assay. Each target will therefore require a positive co...

Can I combine antibodies used in a SignalStar™ assay with direct conjugates?

The CD44 gene encodes 20 exons. Alternative splicing gives rise to CD44s and multiple CD44 variants (CD44v). CD44s is encoded by constant exons 1-5, 16-18, and 20. The CD44 vari...

Which phospho-Akt (Ser473) antibody do you suggest for Immunofluorescence (Immunocytochemistry) (IF-IC) with human samples?

We have several antibodies for detecting the phosphorylation of Akt at Ser 473 that are validated for IF-IC with human samples. These include the following: