PAD1 (human, recombinant)

Peptidyl arginine deiminase 1 (PAD1) is a calcium-dependent enzyme that catalyzes the conversion of arginine residues to citrulline within its cellular protein substrates, resulting in the loss of a positive charge, which can alter protein structure and/or function.^1,2 It exists as a monomer and is composed of a C-terminal catalytic domain and two N-terminal immunoglobulin-like (Ig-like) domains.² PAD1 is primarily expressed in uterine and epidermal cells and generally localized in the cytosol.³ PAD1 citrullinates non-histone proteins, such as keratin, filaggrin, and MEK1, as well as histone H3 at arginine 2 (H3R2), H3R8, H3R17, and H4R3, to regulate epidermal cell progression and embryonic development.^4,5,6 The catalytic activity of PAD1 is lost by deleting the first six N-terminal amino acids.² Decreased Padi1 expression or PAD1 inhibition reduces citrullination of H3R2, H3R8, H3R17, and H4R3 and inhibits primary mouse embryo preimplantation development.⁷ PADI1 mRNA is overexpressed in tumor tissue from patients with triple-negative breast cancer (TNBC), and PAD1 promotes proliferation and epithelial-to-mesenchymal transition (EMT) in a variety of TNBC cell lines in vitro and in mouse xenograft models.⁸ Cayman's PAD1 (human, recombinant) protein can be used for enzyme activity assay and Western blot (WB) applications.

WARNING This product is not for human or veterinary use.

1. van Beers, J.J.B.C., Zendman, A.J.W., Raijmakers, R., et al. Peptidylarginine deiminase expression and activity in PAD2 knock-out and PAD4-low mice. Biochimie 95(2), 299-308 (2013).

2. Saijo, S., Nagai, A., Kinjo, S., et al. Monomeric form of peptidylarginine deiminase type I revealed by X-ray crystallography and small-angle X-ray scattering. J. Mol. Biol. 428(15), 3058-3073 (2016).

3. Nachat, R., Méchin, M.C., Takahara, H., et al. Peptidylarginine deiminase isoforms 1-3 are expressed in the epidermis and involved in the deimination of K₁ and filaggrin. J. Invest. Dermatol. 124(2), 384-393 (2005).

4. Ishida-Yamamoto, A., Senshu, T., Takahashi, H., et al. Decreased deiminated keratin K₁ in psoriatic hyperproliferative epidermis. J. Invest. Dermatol. 114(4), 701-705 (2000).

5. Ishida-Yamamoto, A., Senshu, T., Eady, R.A.J., et al. Sequential reorganization of cornified cell keratin filaments involving filaggrin-mediated compaction and keratin 1 deimination. J. Invest. Dermatol. 118(2), 282-287 (2002).

6. Gonias, S.L., Hembrough, T.A., and Sankovic, M. Cytokeratin 8 functions as a major plasminogen receptor in select epithelial and carcinoma cells. Front Biosci. 6, 1403-1411 (2001).

7. Zhang, X., Liu, X., Zhang, M., et al. Peptidylarginine deiminase 1-catalyzed histone citrullination is essential for early embryo development. Sci. Rep. 6, 38727 (2016).

8. Qin, H., Liu, X., Li, F., et al. PAD1 promotes epithelial-mesenchymal transition and metastasis in triple-negative breast cancer cells by regulating MEK1-ERK1/2-MMP2 signaling. Cancer Lett. 409, 30-41 (2017).

Gorzeń, O., Mikołajczyk-Martinez, A., Mamun, A.A., et al. Isoform-selective PAD2/PAD4 substrates with unnatural amino acids enable cellular peptidylarginine deiminase activity profiling and reveal vimentin citrullination effects in macrophages. Biochemistry 64(19), 4105-4120 (2025).

Yao, H., Cao, G., Liu, Z., et al. Inhibition of netosis with PAD inhibitor attenuates endotoxin shock induced systemic inflammation. Int. J. Mol. Sci. 23(21), 13264 (2022).