Hi,

What kind of load (peptide-BSA ratio) are you aiming for?

I think BSA has several cysteines that you could target, so that would require including thiol reactivity in your peptide: is that an option?

Otherwise, more general approaches using NHS chemistry to target lysines could be considered, but I don't know what your peptide sequence(s) is/are and to what extent conjugation to BSA will affect its activity.

Hope this helps!

There are a lot of methods, that can be applied, depending on your peptide and the sequences. There is a whole journals (e.g.Bioconjugate Chemistry) that only deals with these issues. It is also important, what you want to do after with the Peptide or conjugate. If you want to do an immunization to generate an antibody, the orientation and "connection-point" is very critically for the selectivity and affinity of your further antibody.

In general you can use nucleophilic reactions: I will mention just a few:

- reduced SH groups can be coupled to maleimide groups (There are some crosslinkers.) H ere it was done with DNA and an antibody, but the principle would be the same

https://pubs.rsc.org/en/content/articlelanding/2017/ob/c7ob02216f#!divAbstract

be aware that you have to first reduce -S-S- (Disulfide) groups to obtain -SH groups.

- you can activate Carboxylic acid groups with NHS and couple it to Lysin residues. However you need to be sure that you do not crosslink you peptide intra and intermolecular: Check if the peptide has Lysin residues.

- you can use glutaraldehyde for crosslinking lysin residues. This is easy but you probably get a brought distribution and also crosslink your peptide maybe. Afterwards the imines can be reduced with eg. NaCNBH3 so that they form stable amines

- you can convert glycans in the BSA Structure to Aldehyds by oxidation and couple them to the peptide-Lysin groups. Here you might also have a lot of crosslinking

- I can also recommend activation of BSA with succinimidyl iodoacetate. Here is a publication:

Article Predictable Peptide Conjugation Ratios by Activation of Prot...

- you can introduce an azide group in the peptide and use click chemistry. This is maybe advanced, but you can get a defined ratio. For example if you produce the peptide recombinant, this is a possible option.

This is all depending on A) what your further requirements are. Does the peptide needed to be presented somehow? B) what ratio of conjugation you need. Choose a method carefully.

Good luck!

Most protocols need some experience or optimization. We recently published a paper, presenting a robust method, which delivers a predefined conjugation ratio:

https://www.mdpi.com/2409-9279/1/1/2

If you have any further questions, do not hesitate to ask again.

I can suggest you an useful book: Bioconjugate techniques-Greg T. Hermanson

Yes, I agree with Iris. Hermanson is one of the best books for this purpose. However, for a beginner, this might be too much information.

Thank you all for your kind suggestions

Thank you, Michael!

Hello All,

Need some consultation on how to conjugate hemisuccinates of progesterone and pregnanolone to BSA.

Any simple protocol to make reference to please.

Thanks in advance.

Innocent

i think the book which is mentioned by Iris Miraballes is the very good option about this matter

thank you so much Saeed Ahmed ...