Hi All,

I'd like to know if there are any known enzymes that cleave the sidechains (not the backbones) of lysine or arginine. Smaller enzymes would be better. If unknown for lysine or arginine, please let me know of any enzymes that will cleave the sidechains of any protein.

Thanks,
John

That's a good question. I have never heard of an enzyme that specifically targets the sidechains of a protein's amino acids. However, to begin the search would look at different metabolic enzymes (which might be better prepared to destabilize and cleave C-C bonds) or deaminases (which might be able to take off that ammonia from lysine or the guanidium from arginine). I'm not really sure though. I am also skeptical that these enzymes would be able to work on a protein, I think it would be more likely that they acted on free amino acids or very small peptides (I'm mostly thinking of steric interactions that would prevent an enzyme from getting at the individual side chains on a protein....).

I think technically, any oxidising agent would cleave off the glycine side chain