Blocking Solution

AE-1475 EzBlock Chemi


  • mini PAGE system with a built-in power supply
  • High mode
  • Reduce working space
  • Automatic polarity switching function
  • Quick sealing method
  • Prevent leakage of buffer solution with flexible material in a special wave shape; electrophoresis plate and gel are firmly retained
  • Two-sided constant temperature by using lower buffer solution for reducing the thermostatic smailing
  • A sample is available. Please request the sample through the “Contact Us” menu at the top.

Blocking Agent Selection Guide

Blocking agnet를 선택할 때 3가지 사항을 고려해 보아야 합니다. 
1.항체 적합성 / 2. Interest Protein과의 적합성 / 3. 검출방법
아래에는 일반적으로 사용되는 blocking agent와 그 사용방법에 대해 설명해두었습니다.


  • Non-fat Milk powder (2.5-5% solution), skim milk, is the most commonly used and cheapest blocking agent. Milk should not be used if the protein of interest is phosphorylated.  Milk contains casein, a phosphoprotein that will bind to anti-phospho antibodies which causes non-specific binding and high background noise.  Milk may mask some antigens if they are in low abundance which would cause faint bands. If faint bands occur then decrease concentration to 1% in blocking and antibody solutions or substitute with BSA.
  • Bovine Serum Albumin (BSA): Purified albumin from bovine serum is the second most common blocking agent and is used in a 2-5% concentration. BSA can be used to detect phosphorylated proteins. However, BSA preparations contain tyrosine phosphorylations and will cause high background noise with anti-phosphotyrosine antibodies. Filter BSA before use. Unfiltered BSA may contain contaminating IgG or serum proteins which can cause background noise. BSA is not compatible with lectin probes because it contains carbohydrates that will increase non-specific binding.
  • Fish Gelatin is more commonly used for immunohistochemistry, but can be used for Western blots at 0.1-5% concentrations. Fish gelatin is purified from cold-water fish and can remain liquid at colder temperatures. Fish gelatin does not cross-react with mammalian antibodies because it does not contain mammalian serum proteins. Although, do not use fish gelatin with avidin-biotin detection systems because it contains endogenous biotin.
  • Normal Serum (bovine, rabbit, goat, mouse, etc) is less common because it is used at higher concentrations (5-10%) and is more expensive than milk or BSA. Normal serum carries immunoglobulins that bind to reactive sites on the membrane which prevents nonspecific binding of the labeled IgG antibodies. Use serum from the same species as the secondary antibody. Be sure not to use serum from the same species as the primary antibody because this would cause non-specific binding of the primary antibody across the membrane.
  • Proprietary Commercial Buffers contain pure fractions of proprietary protein without albumin, immunoglobulins, phosphoproteins or biotin. Commercial buffers work efficiently and yield high quality results so less time is spent blocking. Specific protocols for each commercial buffer are available.
  • Protein Free Blocking Agents (Ex: EzBlock Chemi)
    • Polyvinylpyrrolidone (PVP) is a non-protein blocking buffer alternative that is useful for detecting small proteins. PVP is a water-soluble polymer that binds to nitrocellulose and PVDF membranes. PVP is generally used at 0.5-2% concentration and is commonly combined with purified casein or other blocking agents.

Purpose and Application

  • High-speed electrophoresis 20-25min (For high-speed electrophoresis, use with [WSE-7065 EzRunMOPS])
  • SDS-PAGE(SDS-Polyacrylamide Gel Electrophoresis)
  • Native-PAGE
  • High-resolution separation of protein and nucleic acid
  • Purity determination, Estimation of purified product and expressed protein
  • Screening
  • For beginners of electrophoresis and students training