Sharleen Zhou
UC Berkeley
>long time ago my supervisors teached me that trypsin does never cleave the
>peptide-bond between LYS/ARG and PRO. Now, I also tell my students that
>this bond is not cleaved at all. However, in a recent LC/MS analysis we
>measured the masses of two peptides that indicated a tryptictic cleavage
>exactly at this bond (Enzyme: mod. trypsin from Promega). Since I could not
>believe it we additionally sequenced the peptides by Edman degradation and
>it turned out that trypsin has cleaved the LYS-PRO bond.
>On the C-terminal side of the cleavage site there were a number of GLY
>residues. Does anybody know if this may influences the specificity of the
>enzyme? Were my supervisors wrong and trypsin does cleave LYS/ARG-PRO bonds?
>
>best regards
>Petre
>
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>Universitaet Zuerich |
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