Nomenclature	Peptide transporter 1	Peptide transporter 2	Peptide transporter 3	Peptide transporter 4
Systematic nomenclature	SLC15A1	SLC15A2	SLC15A3	SLC15A4
Common abbreviation	PepT1	PepT2	PHT2	PHT1
HGNC, UniProt	SLC15A1, P46059	SLC15A2, Q16348	SLC15A3, Q8IY34	SLC15A4, Q8N697
Endogenous substrates	5-aminolevulinic acid 253, dipeptides 253, tripeptides 253	5-aminolevulinic acid, dipeptides, tripeptides	L-histidine, carnosine, dipeptides, tripeptides	L-histidine, carnosine, dipeptides, tripeptides
Substrates	fMet-Leu-Phe 260, cyclacillin 254, valacyclovir 255, cefadroxil 254, muramyl dipeptide 268	cyclacillin 254, cefadroxil 254	–	valacyclovir 247
Inhibitors (pIC50)	4-AMBA 252, Lys[Z(NO2)]-Pro 258	Lys[Z(NO2)]-Lys[Z(NO2)] 248,267, Lys[Z(NO2)]-Pro	–	–
Radioligands (Kd)	[11C]GlySar, [14C]GlySar, [3H]GlySar	[11C]GlySar, [14C]GlySar, [3H]GlySar	[14C]histidine, [3H]histidine	[14C]histidine, [3H]histidine
Stoichiometry	1 H+: 1 zwitterionic peptide (in)	2 H+: 1 zwitterionic peptide (in)	Unknown	Unknown