Roche Kits are good. Try them

Thank you, Karthigeyan

definitely Chromotek anti-GFP or anti-RFP beads with Alpaca antibodies. you can use as little as 5uL per co-IP reaction

To get rid of heavy or light chains, I  recommend the heavy or light chain specific antibodies from Jackson. They work really well, and can be used at 1:50 000-100 000 dilution. I have better experience with those than with kit for recognizing native antibodies. 

Protein A agarose/sepharose beads from Sigma are also good.

You can omit DDT in your denaturation buffer. This way the heavy and the light chains do not fall apart and you get an Ab band significantly high up on your gel (hopefully your target protein is not that large).

The answer to your last question: It depends if the epitope is liner. If so, it will be still detected in a WB. You must be careful, since you may also detect the Ab from your immunoprecipitation step, hence use a different primary/secondary Ab from a different species.

To avoid the heavy/light chain of IgG, you can use Mouse Anti-rabbit IgG (Conformation Specific) (L27A9) mAb (HRP Conjugate) #5127 from CST. I tried 1:4000 at room temp for 1h, it worked well.

in order to avoid heavy or light chain issues on the blot after immuno-capture we have for many years used the TrueBlot HRP secondary Ab system. gives very clean blots and is very useful when working with exosomes and tetraspanins such as CD9, CD63 and CD81 being at the size range of heavy or light chain of the capture Ab. 1:1000 dilution is recommended and works well. For detection of tetraspanins non-reducing conditions must be used. 

kind regards

ketil