Differentially enriched GO Terms between OA and normal chondrocytes. Differentially synthesized proteins (over-/under-synthesized in OA and uniquely identified proteins) for each group were tested for enrichment in GO terms of biological process and cellular compartment. A high percentage of the proteins belonging to OA group are associated with localization and transport biological functions. The majority of the proteins related to the control group are localized in the extracellular region whereas a higher percentage of the proteins associated with the OA chondrocytes is a part of cellular organelles. Percentages correspond to the number of proteins of each group, associated with a specific term from the total proteins of the specific group. An extended table with the enriched GO terms is provided in Additional file 4.