Effect of 
-Acetylation on Utilization of Lysine Oligopeptides in Escherichia coli
Richard Losick 1 and Charles Gilvarg 1
From the
1 From the Frick Chemical Laboratory, Princeton University, Princeton, New Jersey 08540
A method has been developed for separating 
-acetyllysine oligopeptides from 
-acetylated contaminants by chromatography on carboxymethyl cellulose columns with buffered eluents.
An Escherichia coli lysine auxotroph will utilize -acetyltrilysine as a source of lysine, but will not utilize -acetyl- di- or -acetyltetralysine. It was concluded that the nutritional ineffectiveness of -acetylated di- and tetralysine is due to an inability to penetrate the cell envelope.
Growth on -acetyltrilysine was a linear function of time, and growth rate was dependent on the concentration of the acetylated tripeptide. It was therefore concluded that -acetyltrilysine limits the availability of lysine to the E. coli auxotroph. This property was used to study derepression in the lysine pathway. The pyruvate-aspartic semialdehyde-condensing enzyme and the diaminopimelate epimerase concentrations in cells grown on -acetyltrilysine increased to a considerably lesser extent than dihydrodipicolinic acid reductase, indicating a lack of coordinate repression in the lysine pathway.
Submitted on December 24, 1965
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