Dipeptidyl Peptidase I is a specific enzyme involved in the proteolysis of peptides. The word is pronounced as /ˌdaɪˌpɛptɪdəl ˈpɛptɪdeɪs wʌn/. The term 'dipeptidyl' indicates the enzyme's specificity towards dipeptides, while 'peptidase' identifies it as an enzyme that breaks down peptide bonds. The 'I' in the term denotes the order of this type of enzyme's discovery. The word's phonetic transcription shows the emphasis on the 'pepti-' syllable, while the '-ase' ending sounds like 'ays.'
Dipeptidyl Peptidase I (DPP I) is an enzyme that plays a crucial role in the immune response of the body. It is a lysosomal protease that belongs to the peptidase S9B family. DPP I is primarily found in lysosomes, which are membrane-bound organelles that serve as the cell's waste disposal system.
DPP I is responsible for the proteolytic processing of certain immune-related proteins, including cathelicidins and defensins. It cleaves these precursor proteins into smaller fragments, which are then active and effective in the immune response against pathogens such as bacteria, viruses, and fungi.
This enzyme is particularly important in the activation of neutrophils, a type of white blood cell that constitutes a major part of the immune system. The activation of neutrophils allows them to migrate to sites of infection or inflammation and neutralize invading pathogens.
Deficiencies or mutations in the DPP I gene can lead to a rare genetic disorder called Papillon-Lefèvre syndrome. This syndrome is characterized by severe periodontitis, or inflammation of the gum tissue, which can lead to premature loss of teeth. It is believed that the absence of functional DPP I in individuals with this disorder disrupts the normal processing of immune proteins, compromising the immune response.
In summary, Dipeptidyl Peptidase I is a lysosomal protease that plays a critical role in the immune response by processing immune-related proteins and activating neutrophils.