Initial methionin removal ?

Torsten Borchers borcher at
Sat Mar 4 17:30:24 EST 1995

Joe Mack (mack at wrote:
: In article <D4rx5p.FJy at> agateau at writes:
: >
: >I'd like to know the percentage of proteins in which the initial methionin
: >is cleaved in the mature peptide.
: >Is the enzyme responsible for that identified ?
: >What kind of signal does it need?
: >thanks,
: >Alain

: It depends mainly on the residue immediately following the Met. I don't
: know what they are but they're listed in the papers on the Methionine
: amino peptidases (MAP) - a literature search should find them.

: 	Joe Mack
: 	mack at
: .

I would like to add that besides for "normal" eucaryotic proteins this
behaviour is a problem in production of recombinant proteins in bacteria. 
Since even for one protein not just clear cleavage or no cleavage occurs
very often N-terminal heterogeneity is the result. This is only rarely 
addressed in the literature. A tool to quickly look at this heterogeneity
and that caused by incomplete deformylation is to run isoelectric focusing.

Torsten Boerchers                            Phone: +49-251-980 2876 
Institute for Chemical and                     Fax: +49-251-980 2890
Biochemical Sensor Research (ICB) 
Mendelstr. 7                                                
D-48149 Muenster
Germany                              E-Mail: borcher at

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