. 1999 Oct;181(19):5909–5914. doi: 10.1128/jb.181.19.5909-5914.1999

TABLE 2.

Muropeptide composition and cross-linking of peptidoglycan in E. coli cells^a

Cell type	Relative abundance (mol%) of:						% Cross-linkage^b
Cell type	Tri(A₂pm)	Tri(lysine)	Tetra(A₂pm)	Tetra(lysine)	Tetra(A₂pm)-tetra(A₂pm)	Tetra(lysine)-tetra(A₂pm)	% Cross-linkage^b
Noninduced	6.8	6.7	40.1	8.0	33	4.9	27.5
Induced	6.4	21.4	18.8	22.3	12.1	19.0	26.0

The muropeptide composition was determined by HPLC. The values are presented as area percentages of the sum of all peaks corresponding to monomers and dimers in Fig. 3.

The extent of cross-linkage was determined as the following ratio: dimers/(monomers plus 2 × dimers) (10, 11).