Source-specific composition of N -glycans on human GGT1 (hGGT1). A graphical summary of the predominant structural features of the N-glycans identified on hGGT1 expressed in normal human kidney (left panel) and liver (middle panel) tissues and Pichia pastoris (right panel) is shown. Kidney hGGT1 N-Glycans are dominated by complex type bisected bi- and triantennary structures with a high degree of fucosylation on core and peripheral GlcNAc residues and a low degree of sialylation. Liver hGGT1 N-glycans are dominated by complex-type biantennary structures with a high degree of sialylation and a low degree of core and peripheral fucosylation with modest contributions of triantennary structures. Pichia pastoris-expressed hGGT1 is modified by high-mannose-type N-glycans, ranging in size from Man7GlcNAc2 to Man13GlcNAc2. Symbols: blue box, GlcNAc; green circle, mannose; yellow circle, galactose; red triangle, fucose; purple diamond, N-acetylneuraminic acid.