PADI4 (peptidyl arginine deiminase 4) gene is localized to human chromosome 1p36, and is one of the four PADIs found in humans. PADI4 protein is composed of 663 amino acids encoded by 2238 base pairs of PADI4 cDNA. This protein is expressed in peripheral blood CD3⁺ T cells, CD20⁺ B cells, CD15⁺ neutrophils and CD68⁺ monocytes. It is expressed in haematopoietic tissues, such as spleen, thymus, peripheral blood leucocytes, fetal liver and bone marrow.

Useful for the study of enzyme kinetics, screening inhibitors, and selectivity profiling.

PADIs (peptidyl arginine deiminases) are responsible for the post-translational conversion of peptidylarginine to citrulline, in the presence of calcium ions. Citrullination can result in changes in conformational and functional characteristics of target proteins. In individuals with rheumatoid arthritis (RA), this gene is expressed in hematological cells and synovial tissues, and variant in this gene is linked with susceptibility to RA. The expression of this protein is linked with DNA hypermethylation in acute promyelocytic leukemia (APL), and PAD4/SOX4/PU.1 signaling pathway plays a role in committed differentiation of APL cells into granulocytic cells.