- Human proteome arrays (See Active Array 2.0)
- Customized arrays can include user-specified subsets of human proteins or proteins from other species that are “built to order” (See Custom Active Array 2.0)
No you do not. One of the biggest advantages to our arrays is the flexibility to choose which proteins you want to screen on a custom built array.
- We check multiple slides from every printing batch of arrays for consistent DNA display using a PicoGreen staining dye. This confirms that the printing process was uniform. [LINK TO EXAMPLE]
- We also express protein on multiple slides from every printing batch and confirm acceptable protein display by probing the array with an anti-GST antibody, which detects the GST fusion tag present at the c-terminus of the proteins. Because the tag is at the end of the protein, its presence demonstrates full length display. And as there is one tag per protein this provides some assessment of stoichiometry. We only distribute arrays that have >95% of the spots above a raw intensity value of 10 million. Most of our arrays display >98% above this cutoff. We always include a QC sheet on every batch of arrays. [LINK TO EXAMPLE]
Yes. You can choose to purchase the pre-expressed array, produce the proteins, and screen the array yourself. We will provide you with a detailed protocol for performing the protein expression and screening steps; however, many customers prefer to have our team of experienced professionals perform the screening and analysis through our Ordinatrix screening division.
The lead time to build a custom array is approximately 4 weeks. This may be longer if cDNA cloning is required. Many thousands of clones are already available in compatible vectors. The lead time for the human proteome array is dependent upon your need compared to our current inventory. Lead time for screening services is also dependent upon the number of samples to be screened. We routinely screen 46 samples per week.
Data return will consist of normalized intensity values for each array along with a list of what we consider to be “top hits” based on our expertise
What kind of support can I get if I decide to perform the screening myself? What equipment do I need?
We will provide you with detailed protocols for running the experiments and continued support via phone or email should you have any questions. If it is of interest to you, we also invite you to visit our lab to observe the screening process first hand. To do the screening yourself, the most critical pieces of equipment you will need are an incubating oven that can change from 30 to 15 degrees Celsius to perform the expression of the proteins and a compatible array scanner.
For serum screening, using common dilutions (i.e., 1:50), we need between 150 and 200 µl to cover the complete proteome on the arrays. Ideally, we recommend having an additional 50 µl available to do follow up ELISA assays on any interesting hits.
For screening purified proteins or antibodies, we use a concentration in the range of 1-10 µg/ml, but the specific titer will be sample-specific. What type of samples are compatible with NAPPA screening?
We can use both plasma and serum on our arrays for screening assays. CSF is also compatible, but requires a larger volume of sample due to lower antibody concentrations.