Peptidase 1 (mite)

The first allergen to be purified and characterized was Der p 1, in a 1980 study by Martin D. Chapman and Thomas Platts-Mills. By the end of the decade, it was suspected that Der p 1 was a cysteine protease when its structure showed similarities to that of actinidin and papain. In the mid-1990s, Hewitt et al., Shakib et al., and King et al. proposed methods of Der p 1 promoting allergic responses through its protease activities. == Structure ==

Peptidase 1 is a cysteine protease belonging to the C1 protein family, with a structure similar to that of papain. Initially, peptidase 1 is synthesized as an inactive zymogen, which is activated by enzymatic cleavage. Specificity and cross-reactivity between multiple group 1 allergens is thought to stem from the differences and homologies in structure, particularly regarding the positions of epitopes. Der p 1 Der p 1 is a 25 kDa glycoprotein composed of a 222-amino acid sequence encoded by the gene DERP1. The major kiwifruit cysteine proteinase inhibitor KCPI1 has also been shown to be able to inhibit Der p 1. In its inactive precursor state, f 1 has an 80-amino acid prodomain. Pso o 1's precursor form is thought to be composed of an 81-amino acid sequence. Compared to other forms of peptidase 1, Pso o 1 shares 54% identity with Der f 1, 53% identity with Der p 1, and 53% identity with Eur m 1. A number of amino acid sequences from other peptidase 1 enzymes are shown to be conserved in Pso o 1, including enzymatic amino acids, a N-glycosylation site, and the Der p 1 epitope Leu147-Gln160. == Biological function ==

Peptidase 1 enzymes are found in the fecal pellets of mites. Some of these enzymes have also been located in the mite gut, suggesting that these enzymes play a role in digestion. There, as group 1 mite allergens, peptidase 1 enzymes promote allergic sensitization, usually either by causing epithelial leakage in the respiratory tract through cleavage of the cells' tight junctions or by triggering innate chemokine release through activation of signal transduction pathways. Der p 1 Der p 1 is located in the mid-gut and fecal pellets of the European house dust mite Dermatophagoides pteronyssinus. It has been suggested that the mite's gastrointestinal cells produce Der p 1. CD23 and CD25 are targets of Der p 1, which cleaves these receptors from the surfaces of active B cells and T cells, respectively, and thereby triggers the release of more IgE. Der f 1 shows over 80% cross-reactivity with Der p 1. Like Der p 1, Der f 1 functions by cleaving CD23 to trigger an IgE response. Eur m 1 Eur m 1 is secreted by the Mayne's house dust mite Euroglyphus maynei. Der p 1 and Der f 1 show only low levels of cross-reactivity with Eur m 1. Psoroptic mange in sheep is promoted by the cysteine protease activity of Pso o 1, which targets connective tissues and the molecules of the extracellular matrix. Although Psoroptes belongs to a different order from the house dust mite species, Pso o 1 is classified as a group 1 mite allergen alongside Der p 1, Der f 1, and Eur m 1. == References ==