EDTA for lysozyme action

[Kyle Legate]

Nik_ Duke1 wrote:
> 
> Lysozyme activity is mildly reduced in the presence of chelator, but because it is a small molecule it can do away with upto 1mM EDTA. I know lysozyme is acting only on gram positive bacteria but the practice has been carried on Gram negative bacteria also. You may want to omit lysozyme step altogether if working with E.coli.
> 
No, lysozyme works on gram negative bacteria also, but EDTA helps 
lysozyme cross the LPS layer, as DK has mentioned. Brief sonication can 
also help lysozyme gain access to the cell wall, but there is nothing 
special about the cell wall that make E. coli insensitive to lysozyme. 
In contrast, S. aureus contains an O-acetylation of N-acetylmuramic acid 
that blocks the binding of lysozyme. I have to admit, I'm confused about 
what you mean in the second half of the first sentence I quoted above.