Main muropeptides from <i>L. casei</i> BL23 PG hydrolyzed by Lc-p75 and main products of digestion.

aPeak numbers refer to Figure 2 and Figure S3. New peaks obtained after Lc-p75 digestion, are indicated by letters. bDi, disaccharide dipeptide (L-Ala-D-iGln); Tri, disaccharide tripeptide (L-Ala-D-iGln-L-Lys); Tetra, disaccharide tetrapeptide (L-Ala-D-iGln-L-Lys-D-Ala); Disaccharide, GlcNAc-MurNAc; Ac, acetylation on MurNAc, iGln, isoglutamine; N, D-Asn; A, D-Ala; K, L-Lys. cSodiated molecular ions were the most abundant ones on MALDI-TOF mass spectra for all muropeptides. dPercentage of each peak was calculated as the ratio of the peak area over the sum of areas of all the peaks identified in the corresponding chromatogram (see Table S3). eND, non detected.