Normal Goat Serum (ab7481)

There is no need to heat-inactivate serum if you are using it as a blocking reagent before staining fixed cells or tissue. Heat-inactivation is only necessary if you are using the serum for tissue culture. (The heat inactivates complement, and this eliminates complement-mediated cell lysis).

ab138478 is sterilized, whereas ab7481 is not. That is the only difference between the two products and the reason that ab138478 is more expensive.

ab7481 was not experimentally tested as blocking agent in IP procedures. But I am confident that it should be suitable in pre-clearing steps etc in the IP procedure. Please follow this link to a protocol for IP:
https://www.abcam.com/index.html?pageconfig=resource&rid=11385

Those values are for whole protein value which we supply as a customer service. The total protein value is not considered when making blocking solutions as the percentage used is of the whole serum. Therefore to create a 100 ml or a 10% IHC block you would use 10 ml of serum in 90 ml of diluent.

According to the standard protocol we have for free floating sections, we recommend to incubate the sections with 0.1M PB/0.3% triton/1% blocking serum for at least 1 h.
The whole protocol can be found here:

https://www.abcam.com/index.html?pageconfig=resource&rid=13633

As always certain steps including the amount of blocking agent might have to be optimized according to circumstances like sample, results, etc.

To use this serum for IHC in the blocking step, it does not have to be heat treated. The heat treatment is done to inactivate complement in FCS meant for cell culture for example.

I recommend to aliquot and freeze the serum for storage.

The dilution that works best for your experiment depends on multiple variables so you should do some titrations to find the best dilution. A good starting point for ab7481 is 10%.

ab7481 (Normal Goat Serum) is not heat-inactivated.

Serums will vary in how they are prepared, but there are no specific "grades" that we are aware of. Please note that when using serum as a blocking agent, there is a chance that the animal may have produced antibodies to the antigen in question and if present, the antibodies may bind to the antigen and prevent the primary antibody from binding. If this happens, just switch blocking agents.

We do not measure the total IgG in our goat serums, but generally would estimate total IgG to be ~5-10% of the total serum protein. Concentration of total serum protein is 97mg/ml by Refractometry.