Antibody storage in 5% milk - (Mar/11/2007 )

Hi all,

I just had a quick question about how long I can save my primary antibody and secondary-HRP conjugates diluted in 5% milk/PBS-T? Do I need to add sodium azide or will the azide interfere with HRP signal?

Thanks for your help.

hi icblueskies ! do not use Na-Azide with your secondary antibody as it has deleterious effect on its activity. Na azide inhibits HRP.... secondary antibody should be prepared fresh for good results. however you can store it at -20 C and use it once or twice. regarding primar antibody, it can be stored at -20 C with milk in it and can be used twice or thrice.how ever repeated freeze thawing results in loss of activity of the antibody. to avoid this primary antibody can be stored at 4 C but milk in it is a rich media and supports many microbial growth which might release proteases resulting in the degradation of the antibody.Na-azidecan be added as preservative under such circumstances and used three to four times. but remember if you are usin Na Azide do nt forget to wash thoroughly after primary antibody incubation as it might hinder HRP in the next step. also remember that the performance of the antibody solution decreases as you use repeatedly.
all the best