TABLE 3.

Free oligosaccharide structures in wild-type and ams1Δ cells

^a Glucose unit of each PA-labeled oligosaccharide was determined as described under “Experimental Procedures.”

^b Each fOS amount was based on the peak area of each peak with PA-Glc₆ in the PA-glucose oligomer (TaKaRa; 2 pmol/μl) as a reference.

^c Protein concentration of cell lysates was measured by a BCA assay as described under “Experimental Procedures.” N.D., not detected.

^d Predicted structures of M10G and M6, based on MALDI-TOF MS and various glycosidase digestion analysis.

^e Amount of M8B/M7C was expressed as a combined sum of M8B/M7C glycans that have GlcNAc or ManNAc in their reducing termini. ManNAc residues were generated by epimerization of the N-acetyl group of reducing end GlcNAc during reductive amination in the PA-labeling process as reported previously (45).