Bovine serum albumin is a pure protein adopted in many cases as standard protein in enzyme studies. Skim milk is milk still with its protein casein but devoid of fat (or low-fat). So the proteins are different; albumin and casein. Do you really think that casein is the same thing as albumin?

Hi Mubasher,

Either of them is used to block non-specific binding sites, as you indicated. The difference is mostly where the protein is coming from, blood (BSA), or milk, but either should work fine for your purposes. Cost-wise, skim milk powder is cheaper than BSA, so might be preferable.

Hi Mubasher,

Para el bloqueo de uniones inespecíficas en técnicas de imnunoblot o elisa puedes usar ambas pero será tu experimento la que te indique cual de ellas es la mejor. A veces, en según que condiciones, la BSA te genera más fondo inespecífico que la leche desnatada y viceversa.

En mi laboratorio bloqueamos con leche desnatada como paso previo y los anticuerpos también los diluimos en tBST/leche. Si usamos BSA lo hacemos en el bloqueo y en la dilución de los primarios. No mezclamos los dos tipos de bloqueo.

For the blocking of nonspecific unions in techniques of imnunoblot or elisa you can use both but it will be your experiment that indicates which of them is the best. Sometimes according to what conditions the BSA generates more unspecific bottom than skimmed milk and vice versa.

In my laboratory we block with skimmed milk as a previous step and we also dilute the antibodies in tBST / milk. If we use BSA we do it in blocking and dilution of the primaries. We do not mix the two types of blocking.

@Maurice Ekpenyong, first of all thank you so much for mentioning the difference between BSA & skim milk. I totally agree with you that BSA is a pure protein while skim milk have casein (but low fat). Actually on researchgate & in literature i studied that alternative to BSA you can use Skim milk for blocking (both do function), thats why i asked that as i am doing my research on finding role of human complement proteins, so in my case can i use skim milk instead of BSA, main reason is unavalability of BSA + price difference (BSA price is €4028 while we can get a bottle of skim milk in just €38). Thats why i asked that in my case can i use skim milk or not, because it's my masters research & i am dealing with antibodies so i don't want to waste my time if skim milk can't use. If you have any paper in which skim milk used instead of BSA, share with me, i shall be very thankful.

Thanks

@Dolores Moreno León, Thank you so much for answering my question. Can you please share any of your paper in which you or your colleague worked on antibodies & used skim milk or any other product instead of BSA.

Thanks

Thank you Sir @Jasper B.J. Kamphuis for answering my query. Sir, do you have any paper in which you or any other researcher deals with human complement proteins & antibodies. I want to let you know that my research is to find out the role of human complement proteins against P. aeruginosa. So, in this case can i use Skim milk over BSA, because as you also mentioned that Skim milk (Price almost €38) is cheaper than BSA ( Price: €4028). That's why i need proper scientific evidemce of its use because you know well as you field is also immunotherapy that on quality of our research we can not take risk.

If you can share any published article with me, your help is highly appreciable.

Thanks in advance.

Regards,

Mubasher

Hi Mubasher,

He estado mirando y en los trabajos publicados no se especifica exactamente los protocolos empleados.

Pero te puedo asegurar que el protocolo empleado es el que te adjunto .

saludos

https://academic.oup.com/jnen/article/68/3/262/2917069

I have been looking and the published works do not specify exactly the protocols used. But I can assure you that the protocol used is that I attach it. Cheers

@Dolores Moreno León Thank you for sharing.

Hi，everyone. I have a question with skim milk. When skim milk is dissolved in water, would the solution be opaque or transparent? Because skim milk has no fat in it, the solution should be homogeneous and transparent. Is it right? But with my Daily life experience, any milk in water is white and opaque.

That why I ask so nonsense question is that I worry 3% skim milk blocking is fairly concentrated, if it's opaque, immunofluorescence characterization may be not work, I thank so...Thanks very much.

Hi，everyone. I have a question with skim milk blocking.

When skim milk is dissolved in water, would the solution be opaque or transparent? Because skim milk has no fat in it, the solution should be homogeneous and transparent. Is it right? But with my Daily life experience, any milk in water is white and opaque. That why I ask so nonsense question is that I worry 3% skim milk blocking is fairly concentrated, if it's opaque, immunofluorescence characterization, or any optical detection, may be not work, I thank so...Thanks very much.