Table 1.

Dipeptidyl peptidase 4 (DPP4) substrates.

β-Casomorphin-2	GLP-1* and -2*	MCP
Aprotinin	Glucagon	MDC
Bradykinin	GRF	Morphiceptin
BNP*	GRP	Neuropeptide Y
CLIP	IGF-1	PACAP27
Chromogranin	IL-1β	PACAP38
Endomorphin-1	IL-2	Procalcitonin
Endomorphin-2	GCP-2 (CXCL6)	Peptide YY
Enterostatin	Mig (CXCL9)	PHM
Eotaxin (CCL11)	IP-10 (CXCL10)	RANTES (CCL5)
Monomeric fibrin (α-chain)	I-TAC (CXCL11)	Substance P*
GHRH	SDF-1α and -1β (CXCL12)*	Vasostatin I
GIP*	LD78β (CCL3L1)	VIP

BNP: B-type natriuretic peptide, formerly named brain natriuretic peptide; CLIP: corticotropin-like intermediate lobe peptide; GHRH: growth hormone-releasing hormone; GIP: glucose-dependent insulinotropic polypeptide; GLP-1: glucagon-like peptide 1; GLP-2: glucagon-like peptide 2; GRF: growth hormone-releasing factor; GRP: gastrin-releasing peptide; IGF-1: insulin-like growth factor 1; IL-1β: interleukin-1β; IL-2: interleukin-2; GCP-2: granulocyte chemotactic protein 2; IP-10: interferon γ-inducible protein 10; I-TAC: interferon γ-inducible T cell alpha chemoattractant; SDF-1α: stromal cell-derived factor 1α; SDF-1β: stromal cell-derived factor 1β; LD78β: isoform of macrophage inflammatory protein-1α (MIP-1α); MCP: monocyte chemotactic protein; MDC: macrophage-derived chemokine; PACAP27: pituitary adenylate cyclase-activating peptide 27; PACAP38: pituitary adenylate cyclase-activating peptide 38; PHM: peptide histidine methionine; RANTES: regulated on activation, normal T-cell expressed and secreted; VIP: vasoactive intestinal peptide. ^*Peptides whose endogenous levels of intact to cleaved forms are significantly different following genetic inactivation or chemical inhibition of DPP4 activity in vivo. Adapted from [20, 28, 30].