Figure 4.

Quantitative analysis of glycoprotein metabolism. Proteins and pathways up- or down-regulated over lactation are in red and blue, respectively. (a) Schematic representations of glycoprotein metabolism; (b,c): heat map representation of up- or down-regulated proteins involved in glycan metabolism and nucleotide sugar metabolism, respectively. Protein abundances at n-mo (n = 1–12) are compared to 0-mo of lactation with significance p-values shown in the heat maps. Color legends are at log₂ scale; (d) Examples of immunoblotting validation of proteins expressed in human milk at 0, 1, 3, 6, 9 and 12-mo of lactation. Whey proteins at each stage of lactation were pooled from 10 donors. MWM, molecular weight marker; B4GALT1, Beta-1,4-galactosyltransferase 1; FUCA1, α-l-fucosidase.