Non-Mammalian Blocking Buffers

Arlington Scientific’s line of cost-effective blocking buffers were developed using non-mammalian proteins to provide you with the highest signal to noise ratio possible in your research and manufacturing assay development. Arlington Scientific’s blocking buffers provide superior performance, sensitivity, and stability.

Three Factors Which Come into Play When Finding the Best Blocking Buffer for Your Application:

pH is critical and can have a devastating effect on your end results if it is not correct. A protein’s structure and function both depend heavily on pH.  Arlington Scientific offers you both PBS and TBS formats with different pH values so you can choose which best fits your needs.  pH not only affects the activity of an enzyme but can also affect the charge and shape of the substrate or protein.  All proteins have a narrow pH range at which they function best.  The isoelectric point of a protein is the pH at which a protein carries no net electrical charge and hence is considered neutral. [1] Binding of proteins to various surfaces is affected by a positive or negative charge, therefore the isoelectric point can be critical for optimal protein binding.  When adding a phosphate group to your protein you basically modify the protein from hydrophobic to hydrophilic.[2] Tris based buffers have been found to work very well with the phosphorylated proteins.

Surfactants can reduce non-specific interactions such as hydrophobic interactions between blocking proteins and antigens or antibodies.  Although blocking buffers without surfactants are recommended for Western Blots, blocking buffers with surfactants are highly recommended when developing membrane or lateral flow assays.  Aquatic Block Serum Free formulations contain surfactant: PBS format with Surfynol 485 and Tris format with Tween 20. These Serum Free buffers are also a good option when your assay includes a biotinylated protein. Multiple biotin molecules can be conjugated to a protein of interest, which allows binding of multiple streptavidin, avidin or neutravidin protein molecules and increases the sensitivity of detection of the protein of interest. [3]

Preservatives can have an effect on the performance of some assays, especially those using HRP. Azide Free blocking buffers are sometimes the best option for those assays, whereas Sodium Azide has been used for many years in blocking buffers for Western Blotting procedures. We offer ProClin as a preservative in our Aquatic Block Serum Free/ PBS (PP83P) and Aquatic Block PBS Azide Free (PP71P) formulas.

1. Kirkwood F, Hargreaves D, O’Keefe S, Wilson J. Using isoelectric point to determine the pH for initial protein crystallization trials. Bioinformatics. 2015;31:1444-51.
2. Ardito F, Giuliani M, Perrone D, Troiano G, Lo Muzio L. The crucial role of protein phosphorylation in cell signaling and its use as targeted therapy. International Journal of Molecular Medicine. 2017;40 (2):271-280.
3. Lectez B, Migotti R, Lee SY, Ramirez J, Beraza N, Mansfield B, Sutherland J ,Martinez-Chantar M, Dittmar G. Ubiquitin profiling in liver using a transgenic mouse with biotinylated ubiquitin. Journal of Proteome Research.2014;13(6):3016-26.