Table 1 Differentially expressed proteins in infertile groups with respect fertile controls as revealed by DAVID functional annotations

Proteins associated with molecular functions

Overexpressed: disulfide bond (13), glycoprotein (12), signal peptide (11), hydrolase (9), acetylation (9), EC (7), cytoplasmic vesicle (6), proteolysis (6), secreted (6), peptidase activity (5), mitochondrion (5), endopeptidase activity (4)

Overexpressed: signal peptide (21), glycoprotein (21), disulfide bond (16), secreted (17), extracellular region (16), cytoplasmic vesicle (8), mitochondrion (8), proteolysis (7), generation of precursor metabolites and energy (6), peptidase activity (6), fertilization (3), sperm-egg recognition (2), binding of sperm to zona pellucida (2)

Overexpressed: acetylation (47), phosphoprotein (41), cytoplasm (31), nucleotide binding (30), cytosol (25), mitochondrion (20), ATP binding (20), unfolded protein binding (16), proteolysis (16), transit peptide (15), generation of precursor metabolites and energy (14), oxidoreductase (13), peptidase activity (13), protein folding (12), sexual reproduction (9), protein complex assembly (9), regulation of apoptosis (9), cell cycle process (7), cellular ion homeostasis (5), protein transport (7), cell cycle (7)

Underexpressed: signal peptide (27), secreted (21), extracellular region (23), disfulfide bond (17), response to wounding (6), hydrolase (6), calcium ion binding (6), peptidase inhibitor activity (5), cell adhesion (5), inflammatory response (4), defense response (4)

Underexpressed: signal peptide (17), secreted (12), extracellular region (14), N-glycosylation site (13), disulfide bond (10), growth factor binding (3), pyroglutamic acid (3)

Underexpressed: signal peptide (31), glycoprotein (27), acute inflammatory response (7), disulfide bond (20), response to wounding (9), proteinaceous extracellular matrix (7), homeostatic process (5), vesicle (5), cell adhesion (5)

Activated processes/functions

Proteolysis (6), pyruvate metabolic process (2), cell projection assembly (2), acetyl-CoA C-acetyltransferase activity (2), peptidase activity (5), coenzyme binding (3), protein dimerization activity (4), enzyme inhibitor activity (3)

Glycolysis (4), oxidation reduction (7), proteolysis (7), sexual reproduction (5), generation of precursor metabolites and energy (6), peptidase activity (6), fertilization (3), sperm-egg recognition (2), fatty acid metabolic process (4), sperm-egg recognition (2), binding of sperm to zonapellucida (2), peptidase activity (6), acetyltransferase activity (3), lactate dehydrogenase activity (2), hydrolyase activity (3), Ca²⁺-dependent protein binding (2)

Protein folding (12), generation of precursor metabolites and energy (14), oxidation reduction (13), proteolysis (16), gamete generation (6), glycolysis (6), regulation of apoptosis (9), cellular protein complex assembly (7), sexual reproduction (9), gastrulation (3), single fertilization (3), spermatid differentiation (3), sperm egg recognition (2), unfolded protein binding (16), nucleotide binding (30), purine nucleotide binding (26), peptidase activity (13), coenzyme binding (7), serine hydrolase activity (4)

Downregulated processes/functions

Acute inflammatory response (4), response to wounding (6), cell adhesion (5), NO mediated signal transduction (2), protein-lipid complex remodeling (2), defense response (4), activation of plasma proteins in acute inflammatory response (2); peptidase inhibitor activity (5), calcium ion binding (6), structural molecule activity (5)

Acute phase response (2), acute inflammatory response (2), growth factor binding (3)

Acute inflammatory response (7), response to wounding (9), defense response (8), lipid transport and localization (4), homeostatic process (5), complement activation (2), cell adhesion (5), cell morphogenesis involved in differentiation (3), peptidase inhibitor activity (7), glycosaminoglycan binding (3), protease binding (2), structural molecule activity (5)

Activated pathways

Valine, leucine and isoleucine degradation (3), propanoatemetabolism (2), butanoate metabolism (2), tryptophan metabolism (2), pyruvate metabolism (2), fatty acid metabolism (2), lysine degradation (2), mechanism of gene regulation by peroxisome proliferators via peroxisome proliferator-activated receptor alpha (2)

Propanoatemetabolism (4), pyruvate metabolism (4), glycolysis (3), metabolism of lipids and lipoproteins (5), integration of energy metabolism (4), metabolism of carbohydrates (3)

Integration of energy metabolism (11), diabetes pathways (12), metabolism of proteins (10), TCA cycle (4), metabolism of carbohydrates (5), metabolism of amino acids (5), Parkinson’s disease (6), fatty acid elongation in mitochondria (2)

Downregulated pathways

Complement and coagulation cascades (3), lectin induced complement pathway (2)

Complement and coagulation cascades (5), ECM-receptor interaction (4), glycerolipid metabolism (3), hemostasis (4), complement pathway (2)

Processes/Functions unique to each ROS group

Protease inhibitor (2), endopeptidase inhibitor activity (2), signal peptide (4), anchored to membrane (2), fatty acid metabolism (1), cell membrane (3), glycoprotein (3)

Plasma membrane (3), polymorphism (5), cell surface linked signal transduction (1), spermatogenesis (2)

Mitochondrial envelope (14), organelle lumen (16), TCA cycle (3), metal cluster binding (3), mitochondrial respiratory chain (4), carbohydrate catabolic process (3), monosaccharide metabolic process (4), oxidoreductase activity (3), nucleotide binding (12), regulation of apoptosis (4), ATP binding (4), metal ion binding (11), mitochondrion (25), transit peptide (21), oxidation reduction (11), generation of precursor metabolites and energy (12), cellular respiration (8), organelle lumen (16), oxidative phosphorylation (5), TCA cycle (5), metabolism of carbohydrates and amino acids (4), integration of energy metabolism (8), respiratory chain (4), endoplasmic reticulum(4)

Processes/functions unique to each control group

Secreted (5), signal peptide (5), glycoprotein (5), extracellular region (4), defense response (1), inflammatory response (1)

Signal peptide (5), N-linked glycosylation (4), metal ion binding (3), desmosome (2), cell adhesion (1)

Signal peptide (3), glycoprotein (3), anchoring junction (2), cell–cell junction assembly (1), homophilic cell adhesion (1), negative regulation of peptide secretion (1)

Functional categories related to reproduction/spermatogenesis

 Overexpressed

–

Sexual reproduction (5), fertilization (3), sperm-egg recognition (2), sperm-egg recognition (2), binding of sperm to zona pellucida (2)

Sexual reproduction (9), reproductive cellular process (5), spermatid development/differentiation (3), gamete generation (6), spermatogenesis (5), germ cell development (3), reproductive process in a multicellular organism (6), reproductive developmental process (4)

 Underexpressed

–

Spermatogenesis (2), sperm motility, fertilization, sexual reproduction (1)