DPP4n

DPP4n is a provisional designation used in some scientific reports to refer to a putative isoform or paralog of dipeptidyl peptidase 4 (DPP-4), a serine protease involved in glucose homeostasis and immune modulation. The suffix “n” signals uncertainty or novelty rather than a widely accepted name. As of now, there is no consensus that DPP4n represents a distinct, well-characterized protein, and evidence for its existence and properties remains limited.

Origins and identification of DPP4n have been described in a small number of datasets. Proposed explanations include alternative splicing of the DPP4 transcript, generation of a proteolytic fragment, or the presence of a separate gene in certain species. Reports are largely preliminary, with limited replication or validation at the protein level. Because of this, DPP4n has not been established as a canonical member of the DPP-4 family in major protein databases.

Structure and function attributed to DPP4n are speculative. If real, DPP4n might share characteristics with DPP-4, such as extracellular localization and serine protease activity, but concrete information about its catalytic residues, substrate range, tissue distribution, and physiological role remains unavailable or disputed.

Current status and outlook: DPP4n remains a tentative construct primarily discussed in exploratory genomic and transcriptomic studies. Future work including transcript validation, protein expression analysis, enzymatic assays, and cross-species comparisons would be necessary to determine whether DPP4n is a bona fide protein with defined function.

See also: DPP-4, CD26.